Rio 32hf

[Delphinus]

I run a Rio32hf as the sump return on my 115g and I regret it. Far too much flow, my 30" sump is not nearly long enough (even with several different baffle arrangements I've tried) to shed the microbubbles. I use a filter sock to keep the bubbles down some but it's not really a proper solution, it just helps with it a little.

Unless you have a Herbie overflow, sump returns don't need to give you mondo flow. The general recommendation is to aim for 5-7x volume turnover per hour for a sump return, there's no real need to go beyond that. If you do, you get the noise and you get the microbubbles. You can always increase flow turnover in the main tank itself with a closed loop, powerheads, Tunzes, Seios, Korallia's, etc. (Or even surge tanks.)

I'd consider checking into whether you can return the pump and going with a smaller model. I really wish I had done so. You didn't say what your sump volume is but assuming you have 90g main tank and say an additional 20g in the sump, not taking into account water volume loss due to rock and whatnot, 90+20=110g so anywhere from say 500gph to 800gph at 5' head pressure is the pump you should be looking for.