Plumbing problem

[davwong]

Hi guys

How to prevent back flow from the main tank via the pipe & return pump when there is a power blackout .

[ozy]

My return pipe is above the water surface, so there is no back flow when power failure. But have the problem of salt creep due to the bubbles and splashes.

I think you can get one way check valve for the pipe, similar to those used for air pump. I think SL have some.

[Achilles Tang]

You can make a break siphon.

Simply drill a tiny hole on the return pipe into the tank, just below the water surface.

Once the water level drops... the siphon effect will be broken once air rushes in, ie... no more water back into the sump. But you have to make sure that no algae or snail is blocking the hole when that happens... or...

Alternatively, a water check valve would be good. Get the swing types rather than the ball types as it does affect water flow greatly.

[davwong]

Thanks AT & Ozy, will try to get a water check value.