# Air Break for Canister Filter



## 01722 (Mar 25, 2018)

I bought a canister online. I thought the intake would have an air break to keep the entire tank from emptying in case of some kind of a failure. No air break- does anyone have any good DIY links for this?


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## ken31cay (Oct 9, 2018)

With the canisters I've seen & used the output hose goes back into the aquarium. How would the tank empty if your canister failed or lost power?


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## Cosi (Apr 1, 2020)

Most likely any leaks encountered will be a slow drip through a faulty seal or operator error and not catostrophic. In my experience the drips, if any, always occur immediately after performing maintenance. You could always drill an 1/8" or smaller hole in the intake and inch or two below the normal water line to act as a siphon break. The outlet should already be mounted near the top of the tank. My routine is just to come back to check for drips a few minutes after they have been returned to service following cleaning.


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## 01722 (Mar 25, 2018)

The biggest issues I've read about are popped outlet hoses and seal leaks that empty on the floor while water keeps pulling from the intake. Much of the research on canisters I pulled up mention the downside of terrible leaks that emptied the tank onto the floor... I bought a Polar Aurora canister and all the reviews said it was made by the same company as the Sunsun and they were basically the same unit. They definitely aren't. The Sunsun has the air break among other differences. I'd just like an easy way to ensure the pump stops pulling water when the water level drops to a certain point.


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## Cichlidude (Feb 7, 2010)

01722 said:


> The Sunsun has the air break among other differences. I'd just like an easy way to ensure the pump stops pulling water when the water level drops to a certain point.


Where would that 'air break' be located exactly on the Sunsun?


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## 01722 (Mar 25, 2018)

It's an elbow near the top of the intake inside the tank. It has a sliding sleeve for the water level.


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## Cosi (Apr 1, 2020)

If possible I would avoid any filter that is prone to hoses popping off. I dont have experience with a lot of different brands of canister filters. The canisters I use you have to heat the hose ends in boiling water to soften them just to barely be able slip them over the fittings. The only way to remove them is to cut them off.


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## Deeda (Oct 12, 2012)

I have never yet had a canister filter hoses pop off or develop leaks but have seen this question asked or suggested often. If a hose pops off the filter, drilling a hose in the intake piping won't really be any help if it's the output hosing or connections.

For those people that want to, they usually drill a hole in the intake j-tube approximately 1.5 or 2 inches below the normal water surface of the tank to stop the water flow into the canister but that will eventually cause the filter impeller to seize up due to lack of water.

It's really just easier to make sure your hose and piping connections are secure every time you do maintenance on the filter.


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## Cosi (Apr 1, 2020)

If you have to use a filter that is prone to catastrophic leaks or you just want extra insurance you could drill a small hole in the intake (see red arrow below). The idea is when the water level in tank drops below the intake-hole, the filter starts sucking air and loses suction/siphon. I would also suggest testing it by leaving your filter running while doing a water change and make sure the filter loses suction when the water level reaches the intake-hole. If it doesnt work then you can increase the size of the hole and test again. You will have to make sure the hole stays clear of debris to function properly.


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## Cichlidude (Feb 7, 2010)

01722 said:


> It's an elbow near the top of the intake inside the tank. It has a sliding sleeve for the water level.


That's called a surface skimmer Drilling a hole is the answer.


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