I think I have about 70-80 gallons total here in my system. That's tank, sump and refugium out back.
Tank is 45 gallons and way overbuilt with 3/4" thick acrylic. It's 3'lx2'dx12" tall.
Sump is about the same size as the tank. The biggest reef octopus sump. Another 25 gallons and then the refugium is like 10-15 gallons I think...something like that.
And I give 2, 2 second squirts out of the bottle into the sump. This is not exacting and of no major concern.
That much should raise your ORP about 30-50 points depending on your water's mood.
Excuse my tank. It's been been running for like a year on autopilot just maturing, so I'm just getting corals back in it now.
I pushed things too far last year.
It used to be this and was doing so great...until I screwed up. But that's ok! We can rebuild!
***The really important piece is the UV sterilizer.*** That's been huge for me. But the peroxide helps.
If you dont have a UV, I believe it's a great investment in the long term health of the fish and corals.
But I turn it off for a time when I feed phytoplankton.