refuge questions/advice

Do you have yourself a sump? Whats your theory or idea behind the separate fuge?

 

Since you said high side to low side of -sump- I'm going with you have a sump.... Temp doesn't need to match exactly, my sump/fuge runs about 6 degrees cooler than my display, I have many macros and none of them seem to mind the lower temp. Temp is usually around 71-72ish in sump and main tank 78-81. You can always add a small adjustable heater to keep it at least 72 or so just in case it gets to too cool during the winter.
In terms of powerhead, not necessary, but, will help mix it up a bit and keep a film from forming on water surface and keeping any particulate suspended. So not a bad idea if the flow in there now is not that much.
From my experience, pods do like it slightly cooler. And macros I've kept don't mine the cooler temp, as long as they have some nutrients to consume
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