As far as biological filtration this is as good as it gets. Wet/Dry
sump in freshwater is the way to manage overstocked tanks as far as keeping the
nitrogen cycle running, or being capable of adding
bio-load and not having a mini-cycle: beneficial bacterial will flourish there. Downside: If the sponge media (as preflilters at overflow and between the bio-chamber and sump) get clogged your system may turn into a
nitrate factory; the same applies to canister filters.
As far as mechanical filtration, underwater jets (
DIY) coupled with multiple small powerheads with sponge as prefilter seems to be the most effective one, to the point some suggest it eliminates the need of substrate vacuum. Alternative to this would be placing a
powerhead (or two) with canisters filled with fiber floss, fiber or sponge attached (e.g. AquaClear) close to substrate levels or just manage to build DIY models. Another option is to use "Reverse Filtration" with opposite flowing in a
UGF, but this works only with gravel.
As far as chemical filtration: Activated Charcoal is the standard way to go, here the HOBs and Canisters offer most flexibility although submersible filters (e.g. Fluval) would also do the work. As long as you keep 3 weeks replacement routine, your tank will be well served.
Pepe
Santo Domingo
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