Overflow Help??

[Demon16v]

I want to install an overflow on my tank (not drilled). What I’m afraid of is. What if the power goes out and the overflow losses its siphon. Then the pump in the sump comes back on and starts to pump water back into the tank it will overflow the tank. I looked at a lot of DIY overflows and none of them said anything about them losing the siphon if the power went out. The only one I found that said it would keep the siphon is from Lifereef. Mine looks just like theirs but without the foam. The other ones use a powerhead. I really do not want to go with a powerhead though if I can help it.
Thanks for the help.

 

[fishfarmer]

One thing that will help from emptying your whole sump in case of power failure is a float switch hooked to your sump pump. You can set the switch to any level in your sump, that way when the power comes back on you can limit the amount of water that gets pumped back to your tank. Hopefully your main tank will have enough reservior available for the sump water to go before the switch shuts off the pump. I believe Lifereef sells a float switch. Places like Grainger and McMaster-Carr also sell float switches but these may need to be wired to the pump.

 

[Jacqui]

We have a 105 with a built in overflow. Set up a sump under the overflow from the tank, pump to the refugium and use an overflow box to return to the sump to be skimmed and returned to the tank by a pump. Our overflow box does not lose it's prime...check how they work with your LFS...maybe ours is unique, but I doubt it. It came with the sump system, can't be that special.

 

[fishfarmer]

<blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote

When the power comes back on the powerhead may provide enough vacuum to start the siphon again...

Key word here is may. I run one of those CPR CS50 overflows. They have a square overflow so they are designed to need a powerhead/airline tubing to help clear bubbles. I have run the maximum amount of water through my overflow, but it still collects bubbles. The thing I really worry about is if I'm away and that little airhose gets clogged(which is often). I've heard the U tube overflows are more reliable, too bad I didn't convince myself of that before I bought my current one.

 

[MadMorf]

<blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote

What if the power goes out and the overflow losses its siphon.

I've seen some overflows with a piece of airline tubing attached between the top of U-tube and the venturi connection on a powerhead.

When the power comes back on the powerhead may provide enough vacuum to start the siphon again...

Caveat: I've not tested this myself since I'm not currently using an overflow, but, if I set my 55 up again, I will be doing this to my overflow.

 

[Chucker]

I'd tend to agree with fishfarmer. I flooded my floor countless times with a CPR. I got a LifeReef a few months ago, and find it much more trustworthy. Even if I do get some bubbles in the LifeReef, it's much easier to clear- I simply tip the front of the box down to increase the water flowing thru it, and the high flow carries the bubbles out of the peak of the tube.