It really depends on the pods you're raising.... but most people culture orange tiggerpods from reef nutrition, and those need supplemental feeding. But the upside is they're very hardy to temp and salinity swings.
No. Gas exchange at the surface is usually plenty. Also there is green hair algae growing in my 5g buckets and that helps supplement. In a 20g brute, it might need a bubbler, since the volume to surface area is pretty different.... but even then I suspect you wont need it.
If you wanted it to he the ONLY thing you feed to your tank, you'd likely need several hundred gallons of culture, depending on your stocking. This is a supplemental feed typically.
I think it's just easier to get a 100 micron sieve, and harvest using that, being indiscrininate. Just harvest what you'll feed and leave the rest. I use a baster to suck up pods and run them through the sieve. So long as you dont over harvest, things will be fine. Over harvesting just means it will take a long time for your next harvest heh.
