Plumbing question- check valve

[sttroyiii]

I did a preliminary run on my sump setup this weekend. I made all the errors one would make having never done something like this before, hehe. When I turn off the sump pump, the water wants to drain back down the pipe, and overflow my sump. I only have a 10gal. sump for a 37gal. tank, so this is the way the sump has to be. If I am there, I can turn the ball valve and stop the backflow. During a power failure, I wont. Would installing a check valve(s) somewhere in the riser stop this? My concern is that it will reduce the flow too much. Is that possible? I have a mag7 with 3/4" pipe, T'd for two returns. OR, should I drill a hole somewhere close to the outputs? I like the check valve idea a little better, seems more reliable, but if drilling two holes near the outputs will work, thats def. cheaper. So should I drill a couple of holes, or put a couple of flow-reducing (assuming) check valves in the line?

TIA

 

[jeffbrig]

Drill 2 small hole in the return plumbing right at the water line. When the water level drops, these will draw in air, breaking the syphon and stopping the backflow. Don't rely on a check valve. In the best case, they needlessly restrict your flow. In the worst case, they get crusted up with algae and calcium deposits and fail to operate when you need them.

 

[rottface4]

I agree...don't go with the check valve, they will fail over time. I would drill two holes just below the water line, and allow room in your sump for some water to back flow before the syphon is completely broken.

 

[sttroyiii]

Great, that is exactly the replies I needed!

 

[tomasga]

Here is an image representation of what it should look like, but not exact...

http://www.machconstruction.com/tom/si.jpg

 

[Reeses]

A friendly word of warning, just in case you didn't think of it- be sure to adjust the water in your sump to be able to handle the water traveling back down your lines when the suction is broken.

 

[AZDesertRat]

As Reeses said, always leave enough room in your sump for backflow! Put a permanent mark on the sump and never ever fill it past that point. Even air break holes can and will fail given time, snails and algae have a way of covering things at the worst possible moment.

 

[davidryder]

you could always install a self-destruct. after the water goes down so far, rig the whole thing to blow haha i don't know where i'm at today sorry

 

[sttroyiii]

Lol, thanks for the additional tips. Hopefully my sump will be able to handle the water thats in the pipes. I cant tell yet, since it tries to siphon until I turn the ball valve. I think my mag7 is overkill already, lol.

 

[MCary]

Like an idiot I plumbed my return through the bottom and below the water line and subsequently couldn't use the hole method so I put a PVC check valve in. the check valve failed sooner, not later. I then replaced it with a more expensive model I got from Marine Depot. It also failed in a couple months. Its a flapper valve. Once the hinge gets some salt creep or corrodes a little it can stay open just a little and let water drain back to your sump. This check valve however could be taken apart and cleaned. So it becomes another weekly maintainence item on the checklist.

Mike

 

[sttroyiii]

I drilled the holes even with the water level. Then I checked to see what happens when I unplug the pump. The water drains back to the sump and the little holes slurp a bunch of air in before it starts siphoning. My sump even holds the water without making the refugium spill over into the reservoir! I couldnt have made the dividing wall even a 1/2" lower. Looks likes it works great! Thanks again...

 

[rickh]

MCary---Many setups have the return water running up through the tank bottom. You can run a PVC pipe up to the top of the water level and drill your siphon break hole there. Then continue the pipe back down to your outlets. Like an inverted U. R