This design uses only one vertical pipe in the aquarium, minimizing the presence in the aquarium. This is a very simple siphon overflow design which can’t go wrong. Many prefer a variation of the simplest overflow design: simple siphon overflow Simply put the inlet hose of the canister in the aquarium. I simply do not recommend the siphon overflow designs here in or a drilled tank if one want to use a canister. The canister pumps are not designed to work without a “head pressure” feeding them.

If the water is just flowing though an overflow in such a way that air can get into the piping leading to the canister, the canister will not flow very well up to the aquarium. The water level in the tank needs to be much higher than the drilled hole so that the piping flowing down to the sump is always completely filled with water. Note that a drilled tank needs special considerations if the water flow is down to a canister. But if the aquarium isn’t drilled, some sort of siphon must be used to get the water over the edge of the aquarium and into the sump. If the aquarium is drilled, then the movement of the water back to the sump can be as simple as just hooking up a tube.

There are a huge number of DIY devices on the internet and YouTube that are designed to do this. Then there needs to be a way of moving the water back to the sump and to prevent the aquarium from overflowing. When one uses a sump the pump in the sump moves the water back up to the aquarium.

Cheap overflow box