My setup.

[dtyharry]

All algae needs to grow is carbon from dissolved carbon dioxide, nitrogen from ammonia, nitrate etc and phosphate along with some trace elements like iron. There is no mystery to it as far as I can see. Skimmers have been shown to not really do an awful lot but do reduce bacteria levels. If all you have done differently is to implement the bio pellets and skimmer then it must be its greater efficiency in your case to soak up the nutrients rapidly and a bacteria byproduct to feed your corals.

[Vannpytt]

Yes, but what is the origin? I feed slow, and have had the system first for almost a year, and then again for a few months with cycled water and stone.

Really? As far as I can tell, my scrubber is one of the "largest" in terms of wattage and screensize on this forum, and my tank is not really that large.

[SantaMonica]

Do you also intend to apply this undersizing to my system while I now a few weeks with massive skimmer and pellets have about 1-2mm daily growth on my sps, especially montipora, and almost 0 alga left on sand and rocks?

Yes. Not undersized... underpowered. If you had "algae on the rocks and sand", then something was serious not working.

I did try gac with scrubber without much difference.

Yes, that would not help remove any nutrients.

And the algae growing on the rocks, glass and all over the place?

A simple case of a the high rate of nutrients going to the rock/sand algae first, before making it to the scrubber. The strong scrubbing power of the rock/sand algae overpowered the scrubber. I don't know why. Wait... reading further... I think I do...

for a few months with cycled water and stone.

Ah ha ... I knew there might be a cycle involved somewhere. Same thing that happend to 180rftank when he moved his tank. This is where distributed filtration comes in...

In a cycle, the nutrients come from the rock; they hit the rock surface first, then the corals, then the water column, then the scrubber. Thus the scrubber, or any filter that is "plumbed" to a tank, can't help much because the ammonia does it's damage as it's leaving the rocks.

However, a "distributed filter" can do it. A distributed filter is a filter that is in all parts of the water column at the same time, and thus does not have to wait for nutrients to be "delivered" to it. Although your rocks may seem to have finished cycling, there most certainly were some remaining bits left over. So... how do you remove the nutrients just as they are leaving the rock, before they can touch anything? Your filter would have to be on the surface of all the rocks. Carbon dosing!

As strong as scrubbers are, they can't remove nutrients until the nutrients get to them. And a cycling rock is a nuclear reactor hot spot (even if mostly cycled) of nutrients, with corals setting right on top of them. So, the pellets grow the bacteria which distribute themselves throughout the water column, and thus become a distributed filter, catching the nutrients just as they leave the rocks.

So, your screen was growing good, but there was a HUGE RATE of nutrients going from inside the rocks to the surface of the rocks, where the rock-algae ate it (and the corals suffered). 180rftank got the worse of it because he did a complete tank move with a full cycle, but yours was still enough to cause problems.

Phytoplankton is the earth's natural "distributed filter", but I don't yet know how to concentrate enough live phyto in a tank to do serious filtering. So for situations where real or possible cycles have occured, carbon dosing may be a good temporary distributed filter to use.

[Floyd R Turbo]

Ahhhh!! Finally, an answer on the 180rftnk crash. That makes a lot of sense. Did you post that on that thread?

This also affects being able to cycle a tank with a scrubber. Maybe not as effective as I thought. Still could do it with fish only, but corals would have to wait I think.

[Vannpytt]

The thing that gets me every time I hear that argument is this:

- In a skimmed tank (And I've personally seen lots and lots of short skimmer/pellet cycled tanks with good growth and very little algae) there is non of the problems mentioned, while the detectable nutrient levels are (yes I know you feel there is a difference of rate and level, but if the level is higher, so is the rate) higher. My Acropora is showing massive growth along with my montiporas, (I'm doing pictures to show weekly progress and will post) who has been bleached and stagnated for months. Also, the initial tank with all the same problems was running a year give or take a month, and it also had these problems to the very end before restart. Your cycle argument is therefore flawed if not wrong, or I just have exceptionally shit rock, although I doubt that.

I think this is bacterial, in the lines that my scrubber was too powerfull, removing nutrients at a higher rate than the bacterias could survive on (Remember, my water was run through the screen 8x/h, yes, all of it), and with too little feeding they simply could not survive, leaving the rock and sand without filtering capacity, and thus the scrubber would be "overscrubbing". The liquid food I added went straight to the algae on the rocks, sand and glass, thus there would be nothing competing with it there until it died off, which it most likely would not, as it's only competitor was algae in a remote location. A metaphor would be, the tank and the algae did not even play on the same field. The scrubber got the second servings, the algae on the rocks and sand the first serving, and there was nothing left for the bacteria.

This explanation is in my view, far more logical. Prove me wrong or not.

Point of this "systematic change" is:

- No 6x39w T5HO tube switch every 3 months
- No cleanings once a week
- No need to add RIDICULOUS amounts of food a day (It was built to tackle 23 cubes a day, before understanding that this is probably in excess of 21 cubes more than I feed)

[SantaMonica]

In a skimmed tank (And I've personally seen lots and lots of short skimmer/pellet cycled tanks with good growth and very little algae)

Growth of sps, but not harder to feed corals.

if the level is higher, so is the rate

Not at all. They are completely separate, like voltage and current.

who has been bleached and stagnated for months

Yes, any nutrient problem that causes visible rock and sand algae, and 2-day glass cleanings, is going to slow coral growth.

the initial tank with all the same problems was running a year give or take a month, and it also had these problems to the very end before restart. Your cycle argument is therefore flawed if not wrong

You said you recently had another mini cycle.

removing nutrients at a higher rate than the bacterias could survive on

Most bacteria of interest feed on DOC, as in the ocean. Not inorganics.

leaving the rock and sand without filtering capacity

?? The rock and sand always have filtering capacity.

The liquid food I added went straight to the algae on the rocks, sand and glass

None of the food went straight to any algae, anywhere. Algae does not consume food, at all.

the tank and the algae did not even play on the same field.

This part is true, but the question is why, since everyone else's tanks work properly.

there was nothing left for the bacteria.

There is plenty for bacteria. Bacteria eat DOC from waste, algae, and food. This is the bacteria that feeds the oceans and lakes. The inorganic-eating bacteria from the carbon dosing is a separate issue.

- No 6x39w T5HO tube switch every 3 months
- No cleanings once a week
- No need to add RIDICULOUS amounts of food a day (It was built to tackle 23 cubes a day, before understanding that this is probably in excess of 21 cubes more than I feed)

If yours did not have the "problem", then you would not be able to make your comparison because your corals would have grown greatly, with no rock or sand algae, and with few glass cleanings. And you would have been able to keep more filter feeders, madarins, anthias, flame scallops, scooters, etc, with no target feeding, the same way other people can. The issue is not about a comparison, it's about finding out why your one tank had the problem.

[kotlec]

They are completely separate, like voltage and current.

Dont know how it is important for nutrients, but for electricity it is not true at all. At least how I was told at high school. Voltage and current are directly dependent.

And that is exactly that part , which I can not understand considering rates and levels. No voltage = no current. No levels= no rates.

[Floyd R Turbo]

I, like SM, am an Electical Engineer. You can have voltage and no current. They are not dependent on each other directly, but in relation to resistance, hence V=I*R, or with respect to power, as in P=I*V. His analogy does make sense.

[kotlec]

I got it now. Example:

Skimed tank with measurable nutrients and no problems = there is voltage , but no current. OK. But why in this case nutrients dont make any harm . Why power is not generated in this tank. It has no scrubber at all ! What makes that infinite resistance to stop any current (low rates in our case ) ?

[Vannpytt]

If yours did not have the "problem", then you would not be able to make your comparison because your corals would have grown greatly, with no rock or sand algae, and with few glass cleanings. And you would have been able to keep more filter feeders, madarins, anthias, flame scallops, scooters, etc, with no target feeding, the same way other people can. The issue is not about a comparison, it's about finding out why your one tank had the problem.

Yep, that is true, and if you find a viable solution I'm willing to set it up again. It's not a "scrubber don't work post; it's a "My tank does not work with scrubber even if the parameters are perfect" post.

Another clue would be that it works with pellets and skimmer. Why the tank so wastly outcompetes the scrubber, I do not know.