This may require some delicate adjusting and some downsizing of the pipe below the valve. Place the outlet of this pipe below the water in the sump.Īdjust the valve on the primary overflow to the point where the tube below the valve is completely filled with water. Put the this valved overflow about two inches below the top of the aquarium. Then add a valve to the down pipe of the other overflow. Put the outlet of this overflow above the water in the sump in such a way that it will be very noisy and acts as an alarm for the hobbyist that the primary overflow isn’t working. Make one of the two tubes have a level that starts working at a level about one fourth inch below the top of the aquarium. The above design can easily be made silent by making a double version of them into what is called a “Herbie overflow”. United States Plastics Corporation has the following selection: clear PVC fittings The clear PVC plastic can be obtained form many suppliers on the internet. This is the quietest overflow standpipe design I have found. The outlet is below the water level in the sump. Personally I use a three inch diameter PVC vertical stand pipe filled with pea gravel even with half inch overflows. And the diameter of the silencer tube needs to be at least twice the diameter of the rest of the design. The media in the 2x silencer tube can be anything with roughly a half inch diameter. Put the end of the airline 2 into the tube outlet 4 in case the valve leaks.Īgain, put 2 of these on each aquarium as a cheap insurance policy.Suck on airline 2 until the cap in 1 is filled with water or water comes out the airline.This simple design can be modified to: pipe siphon overflow It is best to put two of these in each aquarium in case one loses vacuum on the siphon for some reason. The level of the aquarium is determined by the height of the open section of horizontal pipe outside the aquarium itself. 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.

Weir overflow box