Sumps with built in wet/drys like Crispy has show in this article are excellent value for experienced fish keepers. Bear in mind the following:
- The amount of water in your tank is determined entirely by the position of the overflow. You cannot run your filter with a lower water level in your tank.
- Having a hole drilled in the bottom of your tank is a risky business. Any leaks at the flange will cause your tank to drain entirely. The overflow must be as watertight as the sides of your tank!
- Overflows can be VERY noisy - fortunately you can make a silencer
- If your pump stops then the water in the return pipe and any water above the level of the overflow will drain into your sump (the narrower your overflow pipe the more water there will be). You must allow for this volume of water to be contained by your sump or it will overflow onto the floor! A good way to prevent this is to fill your sump up with the pump turned off. When the pump is turned on the water level will drop a bit then remain stable (it drops very slowly due to evaporation).
- Sumps are great because they add water volume to your tank, can be hidden from view, can be modified very easily, have huge capacity for filter media, can hold all your aquarium equipment like heaters and thermometers, can increase oxygentation of the water, the list goes on an on.
- Sumps are cool
