Elevated spa drains to spa jets level when pool pump turns off

[budmin]

I have an in-ground pool with an 18" elevated spa that has a spillway into the pool. To achieve independent water circulation in the spa I set the all return and drain lines to fully open. A small amount of water trickles over the spillway which I am ok with rather than potentially the spa draining while the pump is running. Once the pool pump turns off the spa water drains to the spa nozzle level. I have determined I can prevent this by closing the spa drain line (as pictured). With that said, I'm thinking a check valve installed on the drain line below the valve would solve this. If this is correct, which one should I purchase? I don't believe I have enough water head for the newer flapper type and if I go spring unsure how many pounds and would prefer an union connection type for future replacement. The pipes are 2" and I plan to switch over to a salt system in the near future (more corrosive). Thank you!

Spa Drain | Pool Drain | Pool Skimmer 1 | Pool Skimmer 2

 

[Jimrahbe]

Bud,

95% of the time when the spa drains down to just under the jets, the check valve in the spa return line is leaking.

In your case this check valve is right where the label says "Spa Return" in green. It is an old check valve design.

Not sure what a check valve would do in the location you circled. It would obviously have to allow water to flow from the spa into the pump as that is the direction of flow. Stopping water from flowing the other way does not make sense to me.

Thanks,

Jim R.

 

[jlamb5990]

+1 to Jim here. You definitely need a check valve but just on the return side, not suction side. The reason it drains down when the pump is off is because that return valve is halfway open all the time in pool mode. It provides a nice slow waterfall with the pump on but once it all shuts off, all that spa water is finding it’s way back to the pool via gravity and your returns are almost acting as drains.

Get a check valve installed where Jim said and you should be good to go. In the meantime I would adjust you return side valve to be closed all the way while in pool mode and set up a spillway schedule for circulation. That way when the pump is done for the day, pool mode will result in a closed valve to the spa returns and keep that water in overnight.