Does an ATS remove DOC

[leebee]

This is probably on here somewhere, but does an ATS remove enough dissolved organic compound to prevent cyano. I’m currently having a real bad time with it, even though I do regular large water changes and use a skimmer(Bubble King), and use carbon, low fish count, feed minimally, and use ozone, oh, and use GFO. After much research, the best answer is DOC build up, I’m not sure what else to do till I get my scrubber built.

[kotlec]

Scrubber does not remove much doc if at all. It can only add doc in form of vitamins and amino acids witch people other vise dose sometimes .

[Floyd R Turbo]

This is not necessarily true but I think. SM can fill this one it. It depends on the screen growth type to a certain extent which is why you want green growth.

[SantaMonica]

DOC's do not build up, and DOC's do not "cause" cyano. DOC-vitamins, DOC-amino's, and DOC-carbs are what corals eat (in addition to particles). DOC's are 98 percent of all carbon in the ocean and lakes, and make up the biggest food group on earth, which feed everything else. Those DOC-foods are put into the oceans by phytoplankton (algae), and on reefs the benthic algae (seaweeds) contribute also. You'll find corals on reefs growing right next to, and touching, this benthic algae; See studies here:

http://algaescrubber.net/forums/showthread.php?1539-Study-shows-that-corals-prefer-to-grow-touching-turf
http://algaescrubber.net/forums/showthread.php?1509-Corals-vs-Algae&p=14575

DOC's are the limiting ingredient in your tank; bacteria would grow more if it had more DOC (this is why adding vodka/pellets grows bacteria). Cyano bacteria, however, can get it's nitrogen pseudo-directly from food, as well as getting it's carbon from the food. Thus, you'll notice cyano wherever food particles are, such as on the sand bed. That's why they say "cyano does not like flow". Cyano actually loves flow, since flow delivers more nutrients; but the flow blows away the food particles. If you can keep the food particles from settling/attaching, you will probably keep the cyano away as long as your nutrients are low.


I do regular large water changes and use a skimmer(Bubble King), and use carbon, low fish count, feed minimally, and use ozone, oh, and use GFO

But you don't have a scrubber. Waterchanges only remove 20 percent of the nutrients (which then starting rising again immediately), but remove your coral food (and small-fish food) too. Carbon (GAC) removes some food-DOC's, but no nutrients; ozone creates more nutrients by oxidizing organics; GFO remove phosphate only. So you currently have no real way to export useful amounts nitrates. If you do have a DSB, it is not enough, as is often the case.

I would replace everything with a scrubber. That alone will probably get rid of the cyano, unless you are feeding large amounts of liquid particle food, which you are not. If you have sand and rock, you can remove everything else first, since the sand and rock will take care of the ammonia.

[kerry]

Once my scrubber started to grow good my cyano is gone. It really only accumulated where the left over food came to a rest.

[leebee]

I just found this text explaining the function of an ATS, it goes on to suggest that a scrubber promotes bacterial action that consume DOC and N/P. My question is though, without a skimmer, wont this bacteria just build up as it grows and dies.

How Scrubbers Improve Water Clarity, or The Microbial Loop: Our Invisible Friend


This came to me after reading Wetzel's "Limnology: Lake and River Ecosystems", which freshwater types may know of via Walstad's "Ecology of the Planted Aquarium"... But few hobbyists, freshwater or salt-, will ever be moved to buy, let alone read "Limnology", as it's a 1000 page college textbook. Yes, that's right: One. Thousand. Very. Dry. Pages. Happily, though, the last 150 or so are mostly the index and bibliography... Actually, I kid. I found the book to be very rewarding -- it completely overturned my understanding of freshwater aquatic ecology.

I put together Wetzel's emphasis that heterotrophic microbial detrivores, rather than autotrophs such as algae, are the backbone of freshwater ecosystems with a blurb I came across a while back in a science magazine that mentioned the discovery that in marine ecosystems, more than half of the dissolved organic carbon in the water is metabolized by "photoheterotrophic" bacteria. Between that factoid and Wetzel's observation that "up to 99% of organic matter fluxes in aquatic ecosystems are detrital-based" (...meaning that herbivorous and predatory relationships that pass energy up the food chain are trivial compared to the all the stuff that doesn't get eaten but instead passes its stored energy down to the detrivores when it dies) and that "processes are functionally similar in freshwater and marine ecosystems", I felt I had a basis for extrapolating from freshwater temperate lakes to saltwater tropical fish tanks... And then I did some reading on Wikipedia and learned that my flash of insight was apparently the subject of "The Ocean's Food Web, A Changing Paradigm" by Larry Pomeroy, a seminal marine biology paper published in 1974.

Here's the short version for those fluent in Science:

Scrubbers improve aquarium water clarity (which, as noted in the FAQ, means removing discoloration or tinting, not cloudiness or particles suspended in the water) by, paradoxically, dumping dissolved organic carbon into the tank. Since DOC is what's discoloring the water in the first place, you'd think this would worsen the problem, not fix it, but the steady influx of lower molecular weight DOC fosters the growth of bacterioplankton, and they clear up the water by breaking down inedible medium weight DOC molecules with enzymes and consuming high molecular weight (from the hundreds of Daltons into the kD range) DOC compounds through a metabolic pathway facilitated by low molecular weight DOC. How this works is unclear, AFAIK, but bacterioplankton alone can't metabolize kD DOC; if provided with low molecular weight DOC, they can.

Further, a significant portion of the food value scrubbers provide comes from bacterioplankton, as many useful chemicals produced by algae are exactly the sort of low molecular weight DOC that bacteria thrive on, and we know that even in a skimmed system, where the population of bacterioplankton is kept artificially low because skimmers preferentially remove particulate organic carbon, there are still enough around to make vodka dosing work. It's reasonable to conclude that a lot of the DOC coming off a scrubber is being metabolized by bacterioplankton... Indeed, I believe the reason scrubbers are so comprehensively effective is that they support a functioning microbial loop -- a healthy population of heterotrophic bacterioplankton and protists that competes with nuisance algae for mineralized nitrogen and phosphorous in the water column, consumes DOC and detritus from egestion and uneaten food, and keeps these nutrients in circulation in a form that's available to zooplankton and other filter feeders in the aquarium. (...And, yes, I'm well aware that some bacteria and protists are autotrophs and contribute to primary production, but I'm trying to keep this as simple and as short as I can. For the same reason, I'm also avoiding the complexities of the microbial loop, the concepts of eutrophy and oligotrophy, and reducing conditions in the substrate that affect nutrient solubility and concentration -- which, for those of you playing along at home, can be hundreds or even thousands of times higher than the concentration measured in the overlying water!)

And here's the long version for those who'd like to know what the heck I'm talking about:

So, here's the thing... We tend to perceive autotrophs as being at the base of the food chain because plants seem to make something from nothing, and all us humans and the other heterotrophs we see around us depend on the plants, directly or indirectly, for our daily bread. It is nothing less than intuitively obvious to us that the base of the food chain must be the plants... But the real base of the food chain isn't the autotrophs, it's the heterotrophic microbial detrivores (bacteria, fungi, and single-celled organisms called protists) that consume dead organic matter and recycle the nutrients that the autotrophs require. This is why organic gardeners like to say that they don't grow vegetables; they grow good soil, and the veggies take care of themselves.

In aquatic ecosystems, some bacteria (including cyanobacteria, FYI) have adapted to living planktonically in the water and are known as bacterioplankton, though they can also colonize detritus and live in biofilms. In low-nutrient FW lakes with depths exceeding 10-20m, detrivorous bacterioplankton have been found to consume most (80-90% or more) of the organic material sinking out of the top layer of the lake before it reaches the anoxic or anaerobic zone below, where decomposition slows -- meaning the bacterioplankton keep these nutrients in circulation by eating the particulate organic carbon (like dead algae and zooplankton) as it slowly sinks into the depths of the lake, as well as the dissolved organic carbon compounds (like sugars and amino acids) that percolate out of dead and damaged cells. Similar results were found in SW during failed geoengineering experiments involving seeding the ocean with iron to induce phytoplankton blooms, absorb dissolved CO2 from the water, and hopefully identify a method of mitigating global warming. It was hoped that the phyto, once dead, would sink to the seafloor and sequester the carbon it had absorbed, but researchers found that very little organic carbon survived sinking through the upper layers of the ocean.

So what's the big deal about this "organic carbon" that I keep bringing up? Well, it's the medium through which most of the energy in any natural ecosystem is exchanged -- even autotrophs can absorb and metabolize dissolved organic carbon from their surroundings to some minimal degree (...if they didn't, allelopathic chemical warfare wouldn't work). Consider: the sugar in honey and maple syrup and fizzy drinks is dissolved organic carbon; the reason blueberries taste like blueberries and oranges taste like oranges is that they make different kinds of DOC, as well as the same kinds in different concentrations; vitamins are DOC; caffeine is DOC; antibiotics are DOC; venom is DOC; a steak is insoluble, so it's particulate organic carbon, but the amino acids that make up the proteins in the meat are soluble in water -- they were originally DOC before being assembled into proteins, and in some form or another they will be DOC again as the meat breaks down during digestion or decomposition. Organisms break down organic carbon compounds and extract energy from the chemical reactions involved, and they invest energy into organic carbon compounds to assemble chemicals they need to live, grow, and reproduce. Not to belittle the significance of ammonia and orthophosphate, but that's pretty much how life works here on scenic Earth.

This is counterintuitive to hobbyists accustomed to testing for and thinking in terms of mineralized (inorganic) nutrients and ions, particularly saltwater hobbyists who must monitor many additional parameters beyond N, P, and water temperature. ...But ultimately, it's nitrogen and phosphorous that are the enduring problems for most fishkeepers because they accumulate in our water and substrate and can lead to algae growth, dead livestock, and catastrophe. In nature, however, these elements are the two most common limiting nutrients in aquatic systems, meaning that one or the other (usually phosphorous) ends up being depleted and limiting further growth. Thus, in P-limited systems, N can accumulate; in N-limited systems, P can accumulate; if N and P are both accumulating, then the limiting nutrient must be something else. For autotrophic phytoplankton and other algae, that limiting nutrient is most likely to be iron or some other familiar micronutrient, but for heterotrophic bacterioplankton, it turns out to be dissolved organic carbon -- which is why vodka dosing works... It takes several atoms of carbon for an organism to integrate a single atom of nitrogen into itself as it grows, and lots more C than that for a single atom of phosphorous -- marine plankton sampled by dragging a fine-mesh net through the water, for example, have roughly the same collective average ratio of C:N worldwide ("the Redfield ratio"): 106:16:1 or 41:7.2:1 by weight. Autotrophs normally derive the carbon they need from CO2, which means they're responsible for bringing carbon into the system, incorporating it into organic molecules, and building up the total biomass of an ecosystem (this is called "primary production"), while heterotrophs obtain C by consuming organic carbon molecules, like the ethanol in vodka or the acetic acid in vinegar, and ultimately convert organic carbon back to CO2.

Dissolved organic carbon dominates the biological activity of natural aquatic ecosystems, if for no other reason than because particulate organic carbon tends to sink to the bottom, where it decays much more slowly due to low temperatures and the anoxic or anaerobic environment, and it could even end up getting buried and taken out of circulation entirely. DOC molecules come in small, medium, and large sizes. Small molecules can be absorbed and metabolized very quickly by a wide variety of organisms, and they tend to be the richest of the lot in energy (like sugar and other carbohydrates) and/or nutrition (such as amino acids, which can have a C:N ratio as low as 2:1). Heterotrophic bacteria compete aggressively for this important food resource -- also why vodka dosing works, BTW.

Larger DOC molecules, however, have to be broken down into bite-sized chunks to be made useful. Bacteria use enzymes to do this, but as the target molecules grow larger and larger, they tend to become less and less vulnerable to bacterial enzymes. The fraction of DOC that isn't vulnerable, or is only marginally vulnerable, to these enzymes is termed "recalcitrant" because it's slow to break down and be recycled into the food web (...it bears mentioning that fungi have a different arsenal of enzymes and can make a living off of recalcitrant organic carbon, but they prefer particulate detritus). About 95% of the DOC in the oceans is recalcitrant -- not because there's so much of it around, but because the non-recalcitrant fraction gets eaten so quickly. Bacterioplankton can degrade and metabolize large DOC molecules when they have access to a steady supply of small DOC compounds, but absent these nutrients, recalcitrant molecules are pretty much only vulnerable to being broken down by light, a process called "photolysis". In principle, photolysis alone can break down even the largest organic carbon molecules all the way to CO2, but it takes a long time, so recalcitrant DOC tends to accumulate in the water column.

Though these recalcitrant DOC molecules were thought to be all but biologically inert by early researchers, it turns out they're crucial to ecological stability because they provide a reserve of dissolved nutrients -- not just carbon, as the phrase "dissolved organic carbon" would imply, but these large, complex molecules also carry tiny amounts of nitrogen, phosphorous, sulfur, and other crucial nutrients -- that slowly breaks down into edible molecules when struck by light. This trickle of food is enough to sustain a functioning microbial ecosystem in the open water during times of scarcity, preventing a catastrophic crash and loss of biodiversity among the bacterioplankton. And because the detrivores recycle nutrients, their survival means the diatoms and phyto will live to bloom another day, as well.

And what does all this have to do with algae scrubbers? For one thing, algae, like any other organism, releases DOC compounds in the normal course of its life cycle. For another, scrubbers are home to pods, which can't fully digest everything in the algae they eat and thus excrete a lot of organic molecules, some of them degraded to a greater or lesser degree, and some (generally the larger, more recalcitrant ones) all but untouched. And pods are messy eaters -- maybe 10-15% of the DOC in the algae being eaten is lost into the water column when the cells are ruptured (and possibly more than that, given the high flow on an ATS). Further, routine maintenance includes a weekly cleaning, which means that when the filter is reinstalled, it's covered with a host of dead and dying baby pods and algal cells. And, of course, in any large population of living creatures, whether it's a colony of algae or a city of human beings, a certain number of them are dying of natural causes at any given moment, and each one spills forth a complex broth of organic molecules of all sorts and sizes as they decay.

With all that DOC diffusing into the water column, having a scrubber is like drip-feeding your tank vodka -- no, wait... I take that back... Because of the diverse array of small, medium, and large DOC compounds involved, it's vastly better than drip-feeding your tank vodka.

Dosing a saltwater tank with alcohol (or vinegar, or some other source of off-the-shelf, low molecular weight dissolved organic carbon) is a pale imitation of the buffet of DOC available in the ocean, yet even so, it's sufficient to trigger a wave of bacterial growth that is then skimmed off. Given access to DOC, bacterioplankton will grow and reproduce very quickly by absorbing mineralized N and P from the water -- which is probably the "why" behind the empirical knowledge recorded in the scrubber FAQ that it's best to keep a skimmer running for a few weeks after setting up an algae scrubber, even when you're getting lush, dark, crazy fast algae growth in a high-nutrient situation: the skimmer is exporting an unseen bloom of bacterioplankton while the scrubber exports the autotrophs that get all the glory.

Now, to be clear, I'm not disputing that the algae is where the action is. Bacterioplankton do NOT export nutrients, metals, or anything at all... unless you skim them off, but in a mature system, skimming doesn't so much turbocharge your nutrient export capacity as it hobbles the natural waste reclamation and food manufacturing system you're tapping into with an algae scrubber. Bacterioplankton do NOT efficiently sequester nutrients by passing them up to a higher trophic level... less than 10% of the energy in any level passes up to the next, such as from plants to herbivores or prey to predator, and there's some evidence to suggest that the coupling between the microbial detrivores and the animals that eat them is the least efficient of all (but that said, filter feeders can really do a number on plankton). Bacterioplankton is NOT the secret weapon that makes scrubbers work... but bacterioplankton do help scrubbers work better, as evidenced by the (heretofore mysterious) ability of scrubbers to improve water clarity: photolysis alone can't clear up the water, but photolysis along with bacterial enzymes and co-metabolism of large and small DOC molecules can.

In sum, installing a scrubber and removing the skimmer shifts a SW aquarium from a state in which algae have a huge competitive advantage (because they can metabolize the mineralized nitrogen and phosphorous that's accumulating in the system) to one in which bacterioplankton compete effectively for N and P (because DOC is a vast pool of nutrients that autotrophs are all but locked out of) -- and this, it turns out, is as it should be. Such a state is a closer approximation of NSW because it fosters the bacteria known to process most of the dead organic matter in the world's oceans instead of removing them with a skimmer. And because production and biodiversity is being supported at the very bottom of the food chain, where it really counts, it probably also is a state in which an aquarium is less likely to crash.

--

BONUS THEORY: If you've read this far, you deserve a reward! Here's another notion for the interminably curious and the incurably sleepless to chew on...

Another reason that livestock responds so positively to algae scrubbers is that the DOC they release can transport micronutrients by a process called "complexation" (...not to be confused with "chelation"). You've seen nutrients, maybe even in supplements you take every morning, yourself, described as "iron complex" or whatever, yes? All this means is that the iron is being carried around bound to... you guessed it... dissolved organic carbon. In other words, DOC isn't just good for bacterioplankton and zooxanthellic symbionts because they have a taste for it -- it can also bring along iron and manganese, which normally aren't free to move around much in oxygenated water, as well as other micronutrients whose solubility isn't governed so strongly by redox conditions, like molybdenum, copper, and zinc.

So an algae scrubber isn't a "twofer" because it grows bacterioplankton as well as algae... It's a "threefer" because DOC can also facilitate the movement of metallic micronutrients. Yowza!!!

--

ALSO WORTH THINKING ABOUT: Cyanobacteria release a lot of high molecular weight DOC. Since these are energy-intensive compounds to manufacture, that's interesting behavior and must be in some way adaptive... The function of most of these compounds seems to be about managing cyano's microenvironment (for example, cyano in FW is known to evade copper-based herbicides by secreting a polypeptide that adsorbs copper), but it's possible that others are part of cyano's extensive chemical warfare arsenal -- that is to say, they're allelopathic. If so, facilitating their destruction, and presumably the destruction of allelopathic DOC molecules in general, by bacterioplankton may be another valuable service indirectly provided by an algae scrubber.

--

AND ONE OTHER THING: I'm curious as to whether there are anecdotal reports of scrubbers improving water clarity in freshwater systems. I've been playing with a FW blackwater tank (DSB with no filtration and no scrubber -- LMW DOC input comes from floating plants, excreta, and homemade fish food) because the tannins discoloring the water are recalcitrant DOC. When I adjusted the mechanics to minimize flow and induce low-level anoxia at the bottom of the tank, the water darkened; when I returned circulation and properly oxygenated the entire water column, water clarity improved. As the lighting regime, resident population, and other obvious variables in this tank were left unchanged, I believe the change in water clarity can be ascribed to the activity, and likely also the population, of bacterioplankton damping down and ramping up (...though on the other hand, it could also be the result of activity among the epiphytic community -- that is, the biofilms that grow on plants). When oxygen and low molecular weight DOC are available, bacteria are able to consume the recalcitrant tannins at a high enough rate to improve water clarity; when these nutrients are not being circulated effectively, consumption of recalcitrant DOC is reduced or prevented and water clarity suffers as tannins accumulate.

It must be noted, however, that I seeded the water in this tank at the time of its setup with a gallon or two of water from a pond water culture tank I also maintain... FW hobbyists in general do not do this sort of thing, while seeding SW systems with an array of inverts and microorganisms is pretty much SOP. Given that the fauna and flora (excepting the higher plants) in fresh water are, to begin with, stunted versions of the highly diverse populations found in saltwater -- that is, the pods, algae, fish, etc. in FW are all descended from a comparative handful of pioneering species that evolved in the oceans and adapted to life in rivers and lakes -- it's possible that the average FW hobbyist lacks a diverse population of bacterioplankton and thus will not fully benefit from tapping into the microbial loop. That a freshwater scrubber will export nutrients and suppress nuisance algae, however, appears to me to have been adequately demonstrated, and since that's what most people are interested in, this possibility should not deter FW hobbyists from trying algae scrubbers.


I think this is posted on this site somewhere else.

[Ace25]

I just found this text explaining the function of an ATS, it goes on to suggest that a scrubber promotes bacterial action that consume DOC and N/P. My question is though, without a skimmer, wont this bacteria just build up as it grows and dies.

My question to you, after reading these 4 articles below, what makes you think a Skimmer would do anything helpful, like remove excess bacteria? In the last article they prove even with carbon dosing a skimmer can NOT remove the majority of bacteria (just not possible to attach to bubbles to be removed). Just goes to show, be very careful about the advice you listen to. Most people that run bio-pellets really don't have a clue how they work (or how skimmers work for that matter), but will be the first people to tell you "you need a super sized skimmer and have the output of a bio-pellet reactor fed directly into the skimmer", which science has shown to be completely useless (the fact the skimmer won't remove the bacteria which means putting the output of the reactor has zero effect). In the graph below you can see when the skimmer was turned on, bacteria populations actually increased, not decreased like you would expect to see with all the advice that is given about them.
http://www.advancedaquarist.com/2009/1/aafeature2
http://www.advancedaquarist.com/2009/1/aafeature2
http://www.advancedaquarist.com/2010/2/aafeature
http://www.advancedaquarist.com/2011/3/aafeature

http://farm8.staticflickr.com/7208/6987754571_56ac1e98ba_z.jpg


Further, routine maintenance includes a weekly cleaning, which means that when the filter is reinstalled, it's covered with a host of dead and dying baby pods and algal cells.
Not sure I agree with that at all.. the pods are washed away down the sink weekly with the cleaning, and so is any loose algae. The algae left behind after cleaning is usually just the roots, and is firmly attached to the screen and quite alive and healthy. I don't think there is a whole lot of "dead pods or algal cells" getting released into the water after cleaning. I am sure there are some, but I would guess it is extremely minor.

[Floyd R Turbo]

perhaps one of the more interesting observations to emerge from these studies is the fact that all four skimmers tested removed only 20 - 30% of the total organics present in authentic reef tank water.

Fail.

[Ace25]

Yup, big fail, especially when you consider that out of the 20-30% of TOTAL organics removed, the vast majority are things like solid food particles, copepods, things of that nature that are beneficial to leave in the tank.

[RkyRickstr]

Wow, if people only knew.

[Floyd R Turbo]

People do know. They just choose to ignore it and leave the blinders on.

Things will change. There's just no ignoring the facts. It will just take time.

There is a concept that is used with regards to changing the opinion of a group with a particular belief. I believe it is something like when 10-12% of those people change their belief and are 100% confident in their new paradigm, then the rest of the group inevitably will change their belief as well. This is a concept I read/heard about w/r to resistance movements against governments, I think it was recently and about Libya or Egypt. The tipping point in the public belief was reached, and change from that point was inevitable. The same concept applies to almost every aspect of life, and hinges upon a 100% dedication to a belief. Skimmers developed their following and there became such a group of believers, which is why it is considered by the 'majority' to be one of the necessary pieces of equipment.

[kerry]

Thats a great read, and its in pretty simple terms.
SM!!! This post should be put into a sticky with a good name to describe it!!!!

[SantaMonica]

10-12% of those people change their belief

Actually, working in promotion, you find out that it works a bit different than this. If you control the 10%, but the competitor controls the 90%, they will win because 9 out of 10 people will say "seems like everyone is doing...".

The actual trick is to get your percentage over 50, so that people say "seems like more people are now saying...". The problem from day one has been, however, that neither algae nor DOC has a promotion budget. So nothing good about DOC or algae will be promoted, but everything "bad" (untrue) about DOC or algae WILL be promoted... by the competitor. This is the reason that people appear "brainwashed"; you can only believe what's been told to you.

[leebee]

It’s funny, 20 + years ago when I got into marine fish keeping no one really used protein skimmers. Sure, I did see them in shops, but didn’t see any need for one, FW tanks don’t use them, and they work fine( maybe it’s the plants they keep). Thinking about it now I don’t remember having any trouble keeping my tank in quite good condition. No cyanobacteria( didn’t even know what that was back then), no hair algae, no bryopsis, etc. So what has happened? Reading forums, it would seem that there is an endless amount of trouble in reef keeping. So what are we doing wrong? Not many people were keeping coral back then, just a few displays in aquarium shops and at expos. All I did was change about a quarter of the water every 6 weeks and that was it, with tap water! So, is it possible that we over clean our tanks now(skimming), should we just let things work themselves out as far as the biology is concerned?
It has been mentioned before that public aquariums use large protein skimmers and ozone to keep their display clean. I guess they have a reason for this. My head hurts now.

[SantaMonica]

Because they don't have scrubbers.

[Ace25]

The reason you don't see them used in FW is because skimmers do not work in freshwater. They need the salt in order to create micro bubbles. I tried it once.. if you put a skimmer on a FW tank and it just makes large bubbles and won't work properly.

I think the "let the tank find its own natural balance" is the best method to running a reef tank. I feel the current methods you see on sites like RC encourage you to "make your own artificial balance" in order to maintain a tank, and while it can work as well as a natural method, it requires TONS more work and money and you end up playing mad scientist every day with your tank. I did that method for many years, to the point I was just about to toss in the towel because it was really getting to be overwhelming to me... then about that time Santa Monica started spamming all the forums, and getting a lot of crap for it. Even I didn't really believe an ATS could work as good as he said.

I spoke to someone who I thought was super knowledgeable, he is a walking encyclopedia when it comes to anything SW, can name anything in its real scientific name, and he gave me the standard BS line of "ya, that was a failed method in the 80's, you just end up with a worse tank and yellow water" and I initially believed him, but with Santa Monica's persistence with showing successful tanks using an ATS, I finally seen enough to believe it could work good and the person I trusted really didn't know what he was talking about in regards to an ATS. Since I was feeling so overwhelmed and this method seemed to be exactly what I was looking for, I took the plunge, and never looked back. I promoted the ATS so much my local forum banned me because they considered it "snake oil". If you didn't use a skimmer, and a good one at that, then you will fail and have no business on the local site because it goes against everything the admin/mods believe. No loss for me, my tank speaks volumes to me and anyone who sees them. I don't promote the ATS nearly as much as I initially did, but if someone asks me what filtration I use on my tanks, I just open the doors to the sump and show them what is in them, 2 pumps (return pump and ATS pump), small bag of purigen, and a heater with some PVC and a plastic screen. On my tanks, I still believe I need to use purigen, but that is a tank by tank decision. Many people can get by without using carbon or purigen, I feel I am not one of those people, but the small cost of a bottle of purigen is negligible and last a long time since you can recharge it.

[leebee]

My question to you, after reading these 4 articles below, what makes you think a Skimmer would do anything helpful, like remove excess bacteria? In the last article they prove even with carbon dosing a skimmer can NOT remove the majority of bacteria (just not possible to attach to bubbles to be removed).

I read through this last article, and extracted this part.



Overall, the major conclusions from these water column bacteria removal experiments are
1.GAC (Granular Activated Carbon) filtration does not remove bacteria from the water column.
2.Protein skimming (bubbles) removes approximately 30 - 40% of the bacteria in the water column of carbon-treated or organic rich water, but the remainder is not susceptible to bubble-based removal.
3.Steady state bacteria populations in skimmed reef tank water are not subject to further skimmer-based bacteria removal - there is a baseline value that the skimmer will not go below.


So I take from this that skimming is usefull to a point. But then the ocean doesn't have a skimmer(maybe surf).
Oh, for what it's worth, I hate having a skimmer, it's a total pain.

[leebee]

The reason you don't see them used in FW is because skimmers do not work in freshwater. They need the salt in order to create micro bubbles. I tried it once.. if you put a skimmer on a FW tank and it just makes large bubbles and won't work properly.



Obviously I know that skimmers don’t work in FW, I was just trying to make the point that FW tanks function fine without one, and why can’t SW tanks do the same.

[Ace25]

Now add this to what they are saying.

30-40% of bacteria is skimmable, meaning it has the correct hydrophilic properties required to be removed via bubble fraction. Here is the big white elephant in the room, there are both good and bad types of bacteria, a good reef tank always wants to have the majority of the bacteria to be the good type. If you can sustain a greater ratio of good to bad bacteria, the natural population cycles of the bacteria will keep each other in check, the majority will always reproduce more to sustain a majority balance. How do we know that the 30-40% of the bacteria being skimmed is not the good type and you are then skewing the ratio in favor of the bad type to multiply in the tank and wreak havoc.

The answer is, we don't know. So if we don't actually know if we are helping or harming our tank by removing stuff via skimming, then why do it? Why not let the tank find its own natural balance instead, it will make the entire reef tank keeping experience much more peaceful and stable overall. Sure, there are certain scenarios where a skimmer can help, like an accidental extreme overfeeding, but if that happened it would actually be cheaper to do a 100% water change to fix that issue than it is to buy a skimmer for those super rare occasions.

[Ace25]

Obviously I know that skimmers don’t work in FW, I was just trying to make the point that FW tanks function fine without one, and why can’t SW tanks do the same.
LOL, ok.. I wasn't sure. At one point in my life I had no idea and gave an old HOB skimmer to a friend with a FW tank, that was when I learned they didn't work in FW. :)

[Floyd R Turbo]

Now add this to what they are saying.

30-40% of bacteria is skimmable, meaning it has the correct hydrophilic properties required to be removed via bubble fraction. Here is the big white elephant in the room, there are both good and bad types of bacteria, a good reef tank always wants to have the majority of the bacteria to be the good type. If you can sustain a greater ratio of good to bad bacteria, the natural population cycles of the bacteria will keep each other in check, the majority will always reproduce more to sustain a majority balance. How do we know that the 30-40% of the bacteria being skimmed is not the good type and you are then skewing the ratio in favor of the bad type to multiply in the tank and wreak havoc.

The answer is, we don't know. So if we don't actually know if we are helping or harming our tank by removing stuff via skimming, then why do it? Why not let the tank find its own natural balance instead, it will make the entire reef tank keeping experience much more peaceful and stable overall. Sure, there are certain scenarios where a skimmer can help, like an accidental extreme overfeeding, but if that happened it would actually be cheaper to do a 100% water change to fix that issue than it is to buy a skimmer for those super rare occasions.

+1 to that. I started thinking that the second I read that article. Totally sold me against skimmers.

[leebee]

Let me just say this, I am all for going skimmer less. I did it years ago, and I would do it again. I will be building a scrubber as soon as all the parts turn up in the post. The only problem I am seeing now is what happens to all this bacterial plankton after it dies off, does it just settle to the bottom to be consumed by something else, does it release nutrient back into the water column. The basis of carbon dosing is to skim bacteria out after they have done their job, therefor removing N&P. I am worried that this is not happening with an ATS and no skimmer. Maybe SM can add his knowledge on this subject. I know this system works great, and I’m not questioning the effectiveness of an ATS, I just want to get it all worked out.

[Floyd R Turbo]

Even the detritus that everyone is so anal about trapping with filter socks and siphoning out of the sump and blowing off the rock can be left alone

http://algaescrubber.net/forums/showthread.php?1655-Detritus&highlight=detritus

I'm sure the plankton you are talking about falls higher on the chain than this stuff. I wouldn't worry - AT ALL

[Ace25]

I know Santa Monica has some good info for leebee on the subject.

In the mean time, I thought this was a rather neat little learning tool.

http://coolclassroom.org/micro_test/web_lessons/ML/ml.html

[SantaMonica]

what happens to all this bacterial plankton after it dies off

It is eaten by microbes even before it dies. Just like in the ocean, where there is no skimmer.

[leebee]

Sorry to go on about this, but I’m still not sure. A fish tank is a closed ecosystem that we add food to year after year. With no water changes and no means of nutrient export, this has to build up somewhere. It might be at a microbial level, or in the animals and algae that inhabit our tanks. A certain amount of nitrate will convert to free nitrogen through anaerobic bacterial action, and phosphate will absorb into the rocks and sand. The use of an ATS(or a macro refugium, carbon dosing) will be the only way I can see of exporting N&P, as this is something actually being removed. If you are putting food in at one end, something has to remove it at the other, it can’t just keep building up.

Of cause, comparing our little glass boxes to the oceans of the world is a very huge stretch, but they are part of a closed system also, the Earth. Every element on Earth is just re cycled, nothing new is added, the Iron in your steak probably welled out of the ground a billion years ago, and passed through many animals before it got to your plate.

As I stated before, I am an ATS believer, every tank should have one, but I think more is going on than what meets the eye.

[Ace25]

In my opinion, this is where the balance thing comes in. If you can find and maintain the balance of the microbial loop then everything works as it should and gets recycled or removed. For someone like me who feeds on the heavy side, I feel I tend to form a buildup in the DOC/DOM level of the cycle. I don't have enough bacteria to handle the job as quickly as I would like and eventually I see issues I feel are related to a DOC buildup. This is also fairly normal under aquarium conditions. We normally only have a fraction of the amount of bacteria per volume of water as the ocean does, but this can vary greatly from tank to tank, some can have near NSW levels but it is rare.

This is why I use purigen to reduce the DOC levels in my tank to get back to the balance where bacteria can then handle the rest. Easy solution for me I know, stop feeding so much, but I like fat happy fish and I can't help it. Since every tank is different and every person has different habits so it comes down to understanding what issues to look for and how to correct them in order to keep the cycle balanced and working efficiently.

[SantaMonica]

nutrient export, this has to build up somewhere

Food in = algae out.


We normally only have a fraction of the amount of bacteria per volume of water as the ocean does

Aquariums normally have about the same number of bacteria per unit volume as ocean water. What you don't have, is sediment subduction, and therefore unless metals are removed from aquariums by algae or other means, metals will accumulate.

[Ace25]

Aquariums normally have about the same number of bacteria per unit volume as ocean water. What you don't have, is sediment subduction, and therefore unless metals are removed from aquariums by algae or other means, metals will accumulate.
This article seems to counter your statement. Look at Table 1. Bacterial counts from authentic marine water, various control samples, and several reef tanks. http://www.advancedaquarist.com/2011/3/aafeature Oddly though, all the tanks that had a fraction of the bacteria of NSW all had sandbeds, and the ones that were closer to NSW did not.

[SantaMonica]

Yes I've seen that, but I was going off of marine biology studies I've read in the past. More numbers that I should have saved.