AQUANEAT Aquarium Check Valve, One Way Non Return Valve for Air Pump,Fit for 3/16 Inch Airline Tubing, Fish Tank Accessories, 10pcs (Red)

The only issue iv had is one didnt work but thats okay i only needed like 2 of them, also somtimes they wistle but that may not be the case on a pump. I use a water pump that draws air into the water stream, no pump it just sucks ambient air in but if the pressure goes positive it will backflow water and that i cant have happen so i got these valves. Five stars

Works like they should! No complaints

Good product...great price!Highly recommend!

They give peace of mind to some extent. Not a big fan since they do restrict air flow. Put them on after 2 years of just pump and line. Using the tip of an incense stick opened up all 3 valves. They were tough to push in the air line.

WORKS GREAT IN OUR AQUARIUM

Works well.

Half the check valves were completely stuck closed. For the ones that did allow some type of flow through, you have to keep an eye on them because the airline will slip off at some point due to the way the stems are designed as the stem has no barb and just gradually gets fatter which results in constant pressure pushing the airline off the stem. I guess you could glue your airlines on and these check valves (the ones that aren't stuck closed) would work just fine, but I'd recommend just buying a different brand that has at least 1 barb on the stem to keep the airline on rather than a sloped stem as you risk flooding your floor if one of these slip off while you aren't watching.

I added a watering system to my grow tents, and the first time I used it, it emptied 2 whole 5 gallon buckets of water into my plants, after cutting a T in the outlet line of the pump and adding this, it breaks the siphon after the pump turns off so the water stops flowing