question about water level in sump

[motlot77]

so i finally got my sump/fuge up and running. now my question is how do i know how much to top off? the water level fluctuates where my return pump is. do i just wing it?

[MikeyNYC]

do you have a valve on the return line limiting the flow rate back to your main tank?

[reefergeorge]

The level shouldn't fluctuate. I put a marker line on the side and fill it back to that every day.

[motlot77]

yep, got a valve. the water level fluctuates a bit, sort of like a cycle. not really sure why, but it stays w/in about an inch or so.

[weaselslucks]

try this http://www.melevsreef.com/allmysumps.html