Check Valve // back flow prevention

Does anyone know if the 3/4 " check valves at home depot (for under $10) are the same thing as the check valves at the LFS (they sell them for $30. I finally plumbed by 150 but the pump line siphons out to much water when I shut the pump off.

 

I would advise against a mechanical check valve simply because of the flow restriction these pieces produce. There are other options to consider however, can your sump tank handle the amount of backflow into the sump? If it can, then don't worry about it. One simple mod: Drill a small hole in the return line, maybe 1/8" in diameter just below the water level, this will break the syphon when the return pump is switched off. I'm sure someone else can add to this and help you out too.

 

I use a swing check valve on my return into my tank and works great and doesn't restrict flow. I don't know if the ones you are looking at at home depot are the same thing, I couldn't find any 3/4 check valves at my hd store but they had a 1.5" and it was the same thing I ordered online in 3/4". Does it say swing check valve, if so then it's ok to use and probably the same thing the lfs has, they tend to way overprice things. That being said, even though I have a check valve on my return I still keep enough room in the sump/fuge to handle the water that would drain back into there if I didn't have the check valve to ensure there would be no floods onto the floor and would advise against relying on just the check valve. I only use mine to keep all the bubbles out of my tank when I shut the pump off and the water drains down past the return lines and I start the pump back up. Alot of people do what Carpenter said and drill a small hole in your return line right below the waters surface to create a syphon and let less water drain back into the sump.

 

In less than a year, the check valve will become encrusted in tank growth, coralline algea, etc and won't function anyway. Don't depend on them, don't use them. Just drill small hole on your return line right by the elbow (or in the bottom/corner of the elbow) to break the siphon like carpenter said. That's also what I did. The bubbles you'll get from when you start your pump back up are harmless and will be gone in a minute or two.

 

Yes but the bubbles bug me so no bubbles and I have a union on both sides with a cut off on the upper side to change it out if it ever fails. 6 months and valve and return lines are pretty spotless plus I have a powerhead close to the top of the tank and this prevents me from having to cut it off when I cut the pump off also.

 

I agree about not using the check valves.

A simple small (1/8" or so)hole in the return right under water line will suffice, and save you $$ as well.

 

I use a swing check valve and have not had any issues with it. I shut my return pump down weekly for tank maintenance and I make sure it (valve) is functioning properly. I believe if you are diligent with your tank maintenance using a swing check valve doesnt pose a risk. Just be sure you get one that is a swing check with a rubber and plastic flapper inside and DO NOT get a spring check valve which has a metal spring inside, it will rust and cause numerous problems. The Home Depot near me only has spring check valves, I had to order my swing check valve online. Just my .02 worth, I know there are those that will disagree.

 

I drilled the hole. Thanks for the advise. The hole worked great!

 

what if you have holes drilled for your outlets?? how do you stop the over flow from that? coz u cant drill a hole any where for that

 

Your overflows can't have holes drilled, like you said, for obvious reasons. You will have to adjust your sump level to allow for the water drain from the overflow until the water level in the DT drains below the overflow. What I did when I set up my tank was to have my return pump turned off, then filled the tank up and let the water drain into my sump until it reached about 2-3" from the top of my sump. Then I turned the return pump on, which will fill the tank again. Once the tank equilibriates, the sump will be at a certain level. I will then mark that level with a Sharpie and label it "MAX", as maximum water level. My check valve prevents more water from siphon draining from the return line. My return line and check valve on my tank is actually cleaner now after 2 years than it was a few months into installing it.
If you don't have a check valve and use the siphon break hole in the return, use the same method I explained. When the water level is below the overflow, that is where you want to drill the hole in the return tube, just above the waterline. If you have the hole below that line, water will continue to drain until the hole is out of the water and draws air in to break the siphon.