Need help with sump/fuge

[TheReefGeek]

And that is not an auto top off unless you run the RODI into your tank not a garbage can.

When your distance from RODI unit to destination is too great, there is not enough pressure build up in the line to trigger the hydraulic valve (which you didn't mention, and if you don't have, then your waste water production NEVER stops!) to shut down the RODI unit. This is why drinking water systems use pressure bladders to build up the required pressure.

Also relying on a single float valve builds in no redundancy for when it clogs and fails open.