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This might be a silly question, but I'm going to ask anyway...

I've only read that I need check valves if my air pump is below water level. Does that mean it is not needed if my air pump is above water level?

Check valves are quite inexpensive, yes? I think I will invest any way since I'd rather spend a few dollars than ruin my pumps and have to replace them for many more dollars.

steed1172

yup if your air pump is above water level your fine without one as water USUALLY flows down... not up, and check valves are pretty cheap and worth it. in case your water decides to flow up, or something crazy like that.

when you have water up to the top and pump stops the water could start a siphon this is why you place in the check valve ^.^

Nutter

I mount all my airpumps at least 6inches above the water level. I've had water back siphon through an airline left hanging out of the tank a few inches above water level too many times not to mount my pumps higher. Some check valves are not as good as others. I used to have one of my pumps under the tank in the cabinet with check valves on each of the outlets. During a blackout the water pump got filled with water & flooded the inside of my cabinet. Luckily I noticed what was happening fairly quickly & the damage was limited. I even got the pump working again, though it is a bit noiser than it used to be. I like the valves with the little springs in them. I havn't had one of those fail on me before. The ones that just have a little bit of silicone or whatever the stuff is forming a cone in them are the ones that leaked on me & they have all been thrown out.

steed1172

ouch.... good job on fixing it again(noise is just life)... now i haz a question...should more than one check valve be installed? or would they interfere with each other?

Nutter

I would just use one on each line. I don't think it would intefere with the airflow but I don't think there would be much benefit to using two on each line either. Better to just have the pump above the water line & use quality check valves.

flyin-lowe

For the money I always use them. Years ago I had my air pumps on a shelf over 6 inches above the tank. Somebody (not me) knocked one of the pumps off somehow and didn't pick it up. It came unplugged when it fell and started emptying my tank. Before that I never used them, now my air pump sits on the floor anyways so its a must.

michael68

I always install a check valve just before the tube enters the water.

ilikefish

Also note that with an air check valve you get a 35% reduction in air power. Just keep that in mind. Personally I think its unnecessary. Even if you loose electricity or the pump quits the laws of physics wouldn't allow the water to flow up the hose above the water line. But you may want to do it if you'd like to be on the safe side.