I would prioritize flow if your intention is to keep SPS, but if you’re making compromises in equipment then you may have problems with failure down the line. That looks similar to the IceCap 2k gyres that I have used in the past and I think would work just fine for you.
I just use kalkwasser in my ATO chamber. Do you have an ATO?
Yeah. I have a 35 gallon trash can filled with RO/DI water. It's run through a little dosing pump controlled with reef-pi (on a RoboTank). Should I switch to something smaller? I'd be worried using that large a container for CO2 getting in.