Yeah, come to think of it I actually have three filter socks I bought two years ago from a bio-diesel place, I think it was, and they're sitting in a box of fish supplies. I was on top of some old threads on eliminating microbubbles at the time--thinking that and/or some critters from the tap was what was bothering my fish--and I used these hanging from a shower head above my aging barrel in my last "fish room" that was really a bathroom. They were set up to get progressively smaller, maybe even down to 1 micron or something. I could use those inside the colender... For now, though, it's not like it's a terrible thing to try waiting on the tiny pump. (Obviously it's a terrible burden to me to have to spend extra time on these fish! ) So I think I'll try that tonight and see what happens. (And my pump is similar in size to yours--might as well be a fire hose.)