water quality and larval rearing

[Rob]

a 5 micron net would collect so much debris that it would likely clog up in just a few minutes of operation. the best i have found is to use a good foam filter, they collect debris and promote good biological filtration, and are gentle enough to use with very small fish

[venn]

Hi guys. I have been doing a little reading on the topic of fish larval rearing. Joyce Wilkerson wrote in her book that the larvae of clownfish create so much waste, in the form of ammonia, nitrite and nitrate that frequent water changes are necessary. My question pertains more to the green water larval rearing setups I have been reading about on the net. Is ammonia/nitrite/nitrate as much of a concern in these systems? Would the micro-algae feed off of these wastes and keep the levels low? In which case you won’t want to remove them through any form of filtration.
There would still be a problem with DOCs etc.. I was pondering the possibility of a filtration system that works like a dialysis machine. The larvae are fragile so it wouldn’t do to have to much water flow. What if you made a closed loop system that passes filtered water between 2 layers of NITEX mesh( or something like it). It is very expensive stuff, I know(perhaps the cost could be offset by “group buys”…right!? ). I have actually only seen 5 micron mesh so far). The water would not be forced into the larval rearing tank, but would pass between the mesh and pick up DOCs through passive diffusion. They could be filtered out using carbon and or protein skimming. The algae and larvae would remain in the tank undisturbed feeding off of the larvae waste. Crazy idea, huh?! Just a thought. Is it crazy enough to work?

[venn]

Ahh. My thought was that maybe since there was no forced water flow across the mesh it might not clog very quickly. All the particulate would stay in the tank to be siphoned out, but the smaller diffuseable stuff could cross by passive diffusion. I was trying to come up with a method to clean the water without filtering out the particulate(microalgae). A foam filter would clog pretty fast in a green water setup I'd imagine. This came about from my readings about green water rearing of centropyges.

Incidently I heard you say you are doing some clownfish rearing and wonder when do you start to use the foam filter?

Thanks for your input Rob. I continue to enjoy your show when I'm walking/driving to work, out for a jog,...
Thanks for the time you put into it.
Brad

[Rob]

ok, i think i misunderstood your original thought.. yes, if its not being passed through like an active filter media it will last longer, but wont filter nearly as much out.

as far as the foam filter, i start using them after a few weeks of age, and they dont clog up that fast. but that said i also dont raise my clowns in greenwater at all.