Siphon break on a canister filter.

[Sub-Mariner]

This will work on any canister filter but I did this specifically on my Eheim 2262. I know a lot will say this is not needed but it's not hurting anything doing it so why not? It's just another fail safe for that 1 in a million scenario.

I used 3/4" PVC for the intake and a spraybar. If you've ever removed the intake strainer and put you hand near the bottom of the intake tube while the 2262 is running, you'll know that this thing will try to suck your hand in.

I was worried about having a hole that was too big and affecting the suction at the bottom or a hole that was too small that wouldn't break the siphon.

I found that a 7/32" hole worked flawlessly. I ended up a 3/16" pull through grommet but instead of using the pull part I used the larger end which is slightly larger than the 7/32" hole. You want a tight fit or else you'll lose your siphon should the water level fall below the hole.

Pull through grommet.



7/32" hole at the top of the intake.





This video shows the 7/32" hole is able to break the siphon.
*Dont' mind the other pipe to the right of the intake, that is my good intake. The intake in the video was a scrap piece I had left over.*

This video shows that the rubber grommet creates a tight seal even when the water level is below it IE: doing a water change. DON'T forget to put the rubber grommet in the hole before draining your water for a water change or else you're going to have to re-prime your canister.

 

[TheWolfman]

So what’s the purpose of the syphon brake?

 

[Sub-Mariner]

It breaks the siphon on the filter.

I keep my intake about 4" from the bottom of the tank. If a seal on the the filter were to fail and instead of leaking it started gushing it will only empty the top 1-2 "of water instead of the whole tank down to my intake.

I probably will never need it but you never know.

 

[Coryloach]

I keep the intakes half way up, generally for a completely different reason....but it works as a siphon break. From experience, the tanks themselves leak before any external filter would. I have had 3 broken tanks in the past while the same filters are still in use...

P>S. Generally filters should not be used to gather the gunk of the tank or the bacteria that develops in the filter will be the wrong type. Symptoms are spikes, especially nitrite spikes. I also always use pre-filters on the intakes for the same reason. So all my intakes are way up, none collects anything but water.

 

[TheWolfman]

There’s nothing wrong with a little ocd. The only time I’ve ever had a canister leak was right after a service and it was a lid that wasn’t on properly. The only thing I don’t get is if the grommet keeps the filter running during water changes then how is it going to brake the syphon?