Preventing Return Back Siphon Inexpensively And Reliably

[wsboyette]

I have discovered a means of preventing back siphon and subsequent sump overflow without having to purchase an expensive check valve of questionable reliability. As is obvious, it would only take a tiny bit of debris or buildup in such a valve to cause it not to seal completely and cause a flood. A tiny hole drilled in the return at the minimum desired water level inside the tank is enough to prevent back siphon without fail (1/32 - 1/16" is enough). During normal operation, the hole is submerged and (due to its tiny size) reduction of the flow at the return's output is negligible. When the level of the tank drops to the hole during power down, air will be admitted to the return and the siphon will be broken. I am using this on my Berlin setup, and it works great ! Easy maintenance too.... Instead of dismantling and cleaning a check valve, a prick of a toothpick at water change time is all that's needed to ensure continued reliability.

 

[WannaRace]

:mrgreen:

 

[Northstar24]

The overflow plumbing kits from All Glass come with these holes already drilled

 

[Zissou]

Ah, but it's while you're away from home that the power will shut off, just as a snail is going right over it.

I always make two holes. :mrgreen:

 

[wsboyette]

Shouldn't be a problem if another tiny hole is drilled in the opposite side, or 3 holes 120 degrees apart.