I'll start by Telling you my Goals.
I would like to add a sump for increased water volume and ease of water changes only, I do not intend to use it for filtration or a refugium of any sort.
My idea is this, I would like to get 2 10g liquid containers that can be pressurized (nothing high just enough to complete a full circuit from main tank to containers and back with 1 pump). I would pump water into the containers from the main tank and the resulting pressure when they fill completely would then force it back into my main tank. I would install quick disconnects or ball valves and normal fittings for the in&out lines that I could disconnect and then carry the containers to the sink for changing.
Filtration will be handled by a new API nexx canister filter and my existing bubble filter.
Has anyone ever tried this? Does anyone see any problems with the idea? It will basically work exactly like the Nexx does minus the filtration.