I recently purchased a CPR CITR In-Tank Refugium
for the purpose of breeding copepods. I don't have any fish that I think will eat them at the moment, but I like the little buggers. I also wanted to try breeding brine shrimp so I bought some brine shrimp eggs along with the copepods. I put a half inch or so of sand in the in tank refugium. I also put in a small piece of porous, former live rock that has since been dried and some cheato, which I understand copepods eat.
Also, I had wanted to put 2 inches of sand in the in tank refugium, but the flimsy suction cups the thing came with couldn't support the weight so I settled for 1/2 an inch or so. There is currently a tall plastic kitchen utensil propping the in tank refugium up to help take some of the load off of the suction cups until I can find a better solution.
Anyhow, the in tank refugium comes with a Rio Powerhead 180 that mounts on the side of the in tank refugium and pushes water from the aquarium into the in tank refugium to keep the water moving between them. When I turned the powerhead on, it began whipping around violently all of the copepods and brine fish eggs I'd bought from the store and put in the in tank refugium. I turned the powerhead off, thinking it didn't seem likely any of them would survive in there, let alone start to breed.
So that there was some flow I moved the return tube from my wet/dry near the several holes on the side of the in tank refugium and twisted the adjustable spout on the return tube so that the water flowed toward the in tank refugium.
My question is, do you think the gentle flow resulting from having the wet/dry's return tube nearby and facing the holes in the in tank refugium is enough to keep things healthy, or do I need to turn the Rio Powerhead 180 back on so that a lot of water is drawn from the aquarium into one side of the in tank refugium and pushed out the other side?