Check Valve for return

[phish1627]

Working on the plumbing for my first reef tank (40 gallon display with sump). Guy at my lfs told me a check valve was a must for my return plumbing. I plan on drilling a small anti-siphon hole just below the water surface. I also have a fairly decent sized sump that should allow for a good amount of water in case some water siphons back before getting to the anti siphon hole. Is a check valve necessary? They aren’t super cheap and I am reading they aren’t incredibly reliable.

 

[tsharpe291]

I don't believe you need one, ive not used one ever in any tank ive had in the last 20 years.
just make sure your sump can handle it which sounds like you are.

 

[JumboShrimp]

Exactly... @tsharpe291 just beat me to it. Frankly, when I was setting up my two 150-gallon tanks, I bought each return pipe a quality ($) check valve. Come to find out, IMO, if you configure things right vis-a-vis your sump capacity, they are an unnecessary expense. (Not to mention every time I kick off the return pump, the check valves clamp shut with a sonic-boom that rattles the house; slight exaggeration, but it can't be helpful to the system. ) Instead, just point your water return flanges high (shallow) in your tank... which is great for aeration by the way... and physically the water can only backflow into your sump from your tank by 'that' amount when the power gets cut. More than that is impossible. (I don't even have a hole drilled in the flange-- the shallowness of the return into the tank will end the back flow at an acceptable point.)

Bottom line: Have a big enough sump, and test the system by cutting off the power enough times that you can have restful sleep at night-- then put the money you saved into a different part of your system.

 

[Gumbies R Us]

@BeanAnimal

 

[exnisstech]

Not at all necessary. If the sump is too small to handle the back flow when the return is off then you need a larger sump. Never depend on a check valve to prevent a flood. They can be helpful to prevent a rush of air when the pump is turned back.