Agree! A DIY sump can be had for 1/2 the price of say the Fluval FX.
Larger water volume (so you can stock more).
Equipment out of sight.
Constant water level in show tank - in spite of evaporation.
Easier dosing of ferts, etc .... no need to mix, just dump in sump.
Ability to act as fuge ... eg. keep your feeders in the sump so they won't get eaten.
Ability to do fancy things like a reverse day-light algae/plant NO3
absorption unit ... just like the salties!
Much higher gas exchange capacity.
You can service multiple tanks with one large sump - less maintenance .... that's why LFS
's has them.
Noise - sump/overflow generally entrain air in the plumbing ... the air water mix falling down can be loud .... this can be reduced, but never as quiet as a good canister.
Risk of flooding unless it is properly setup. Drilled tanks are safer than overflows.
If you inject CO2
, the sump will outgas it - although Chuck's page has a CO2
injected sump system that is sealed.... but I suspect he will still use more CO2
than a canister.