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View Full Version : setup for 550Gl re designed



dirk_brijs
05-16-2011, 03:42 AM
mister santa after your comments in last design ( viewtopic.php?f=3&t=1156 (http://algaescrubber.net/forums/viewtopic.php?f=3&t=1156) )
i re designed my planned scrubber for my 550gl display tank
any comments and suggestions are always welcome.

SantaMonica
05-16-2011, 09:46 AM
Yep looks great. Just have reflectors on the outside panels.

dirk_brijs
05-16-2011, 02:21 PM
Yep looks great. Just have reflectors on the outside panels.

it has to be reflectors as I was intending to just use black acrylic for the box around it. On the drawing it shows transparant for viewing but it wont be in real?

dirk_brijs
12-30-2011, 06:46 AM
Good thing I havent started the actual build of this design yet.
Now with the new calculations this seem way overkill?
What would actually happen with a too large scrubber?
Guess will have to go back to the drawing board and go with an about 130SqI screen which allows me to feed 10 Cubes of frozen food per day right?
Please advise

Ace25
12-30-2011, 10:29 AM
I think under most normal conditions if you make a scrubber to large nothing bad happens, you just don't get the full growth on the screen. But if you have a tank that is lacking in biological surface area (ie. having 20lbs of live rock in a 100G system) then having a scrubber that is too large can become an issue because you don't have a balance between algae and bacteria. The algae will grow as long as you give it food, and release dissolved organics in the process, which under normal conditions bacteria and corals in the tank can maintain DOCs at a certain safe level, but if you don't have enough surface area for the bacteria to grow you could have an imbalance in the system where the algae becomes a contributor to problems in the tank instead of helping remove them. That is a very rare circumstance though and something 99% of people would probably never have to worry about.

I would seriously rethink using CFLs at this point and go with LEDs. I know this post was started well before LEDs really took off, but since your still in the design process I would highly recommend rethinking your lighting choice.

dtyharry
12-30-2011, 02:54 PM
I do not agree with Ace25 at all on the imbalance thing. All the studies show that algae only start to release doc to any significant degree if they are left 'ungrazed'. If you are scraping your screen regularly the algae are constantly growing and not releasing excess photosynthate into the water.
The only negative to a too large screen as far as I can see is wasted electricity which here in the uk is expensive and lack of proper growth if not feeding enough.

Ace25
12-30-2011, 05:25 PM
All the studies show that algae only start to release doc to any significant degree if they are left 'ungrazed'.
Please point me to "all the studies" that show this.

The studies I read show that "grazed" algae releases far more DOCs than "ungrazed" algae. Algae on screens is constantly being grazed upon by copepods.

http://www.jstor.org/pss/2835565

The release of dissolved organic carbon (DOC) by Daphnia pulex de Geer from six different algal species was evaluated using 14 C-labeled algae and analyzing the labeled dissolved organic matter. Up to 17% of the algal carbon ingested was initially lost as DOC from algae damaged during feeding. Only about 14% of the carbon from algae swallowed whole is released during ingestion. Additional DOC is produced by secretion from Daphnia and by leaching from their feces. More than 10% of the algal particulate organic carbon removed from suspension by grazing was transformed to DOC in the case of all food species except the very small green alga Stichococcus.

SantaMonica
12-30-2011, 09:39 PM
Please point me to "all the studies" that show this.

There are hundreds. Just google "particulate and dissolved organic carbon".


The studies I read show that "grazed" algae releases far more DOCs than "ungrazed" algae. Algae on screens is constantly being grazed upon by copepods.

You are talking about something different. You are referring to the consumption of algae by pods, whereby the pods convert the algae into dissolved "waste". He, however, was referring to how the algae itself produces more dissolved organics when its growth slows down. Thus, less physical particulates, but more dissolved. It's very common in reef studies, especially now with ocean acidification.

dtyharry
12-31-2011, 07:47 AM
Yes, when the turf algaes are constantly grazed and kept at a very short length, the inorganic carbon they fix by photosynthesis is rapidly passed up the food chain, and most of their energy is taken up to promote regrowth.
It is only when the growth is left unchecked that the photosynthate produced is not required for growth and is 'leaked' into the surrounding water in the form of dissolved organics.

Ace25
12-31-2011, 10:03 AM
You are talking about something different. You are referring to the consumption of algae by pods, whereby the pods convert the algae into dissolved "waste". He, however, was referring to how the algae itself produces more dissolved organics when its growth slows down. Thus, less physical particulates, but more dissolved. It's very common in reef studies, especially now with ocean acidification.
dtharry stated that ungrazed algae releases more DOCs than grazed algae. I disagree and provided science to back it up. I really don't care how the DOCs get released, if it comes from algae leaching it directly or comes from grazing and consumption, bottom line is that algae being constantly grazed upon will release more DOCs into the water column than non grazed, especially when talking about algae in a screen/ATS environment due to it being an ideal living space for copepeds.

I understand what he is saying, when algae reaches a certain length it does not grow any longer, at which point it will release more DOCs. I completely understand and agree with that, but I do not agree that overall the algae will release more DOCs by being left alone especially in an ATS setup. By the time algae reaches its max growing length on an ATS screen I would imagine a good portion of that algae will be eaten/released into the water from copepods. If we were talking about putting a empty clean tank with no predators and a handful of algae, sure, that scenario that algae would release the DOCs more as it grows without predatation, but that isn't a scenario we can duplicate in our standard aquariums.

This gets back to the original question by the OP, can an ATS made too large cause issues. I still say yes, it is possible, but not probable under most normal conditions. Let me paint a very extreme scenario that no one would ever do just to get the point across. Put in a 10' long x 2' tall screen with proper flow on lighting on a 20G tank, feed the tank 50 cubes a day, the screen grows fantastic but the tank does terrible because there is not enough bacteria/bio filtration to handle that much DOCs coming into the system, yet you could easily have a 0/0 N/P reading in that scenario because the screen is working.

SantaMonica
12-31-2011, 12:30 PM
Actually, in a real reef, there probably are more predators (pods) to eat the algae than there are in a scrubber, because algae in the wild is not cleaned every week.

As for the giant-scrubber example, it would probably do better than a regular-sized scrubber, because the chlorophyll-to-coral ratio would be similar to a real reef. My calculations showed that a regular 100g tank would need a standing stock of at least 4 pounds (remaining after a cleaning) of algae to equal a real reef. The levels of algae/chlorophyll (both benthic and planktonic) on reefs are well-measured and quantified, and the number of corals/gallon on reefs are far less, thus real reefs have a much larger algae-to-coral ratio than tanks do.

dtyharry
12-31-2011, 03:03 PM
For anyone reading this please be assured that Ace is wrong on the algae dissolved organic carbon issue
Algae that is being constantly grazed passes its harvested energy rapidly up the food chain which is why coral reefs can support such a high biomass in comparison with other ocean environments.
Yes when a predator eats the algae some doc may leak out as his highlighted study shows but this is minimal in terms of the overall amounts concerned.
There is a huge difference between doc being released into the water and algae biomass being consumed and moved up the food chain. Organic and inorganic nutrients are completely different entities.

dirk_brijs
01-02-2012, 02:18 AM
OK cam up with the following.
It would become one instead of 2 screens.
The screen would be 27x8 which makes 216 SqI which would be sufficient for about 18Cubes of frozen food. ( should do for a 500Gl tank)
http://i49.photobucket.com/albums/f298/oxbow70/scrubber3.png
as for flow I was thinking about 1500Gph
the lighting would be 6 x 23WCFL bulbs on each side so a total of 12 x 23W CFL with reflectors built inside.
- Would this be enough light and flow
- was the calculation of the screen size correct?
please advise as I would like to start design ASAP

SantaMonica
01-02-2012, 05:14 AM
Looks good.

dirk_brijs
01-03-2012, 06:59 AM
how about the lighting?
overkill or....?
and how long should I run them for?

SantaMonica
01-03-2012, 12:57 PM
18 hours.