Back flow valve location

[kcautodoc]

Hey all. We have a pool with a spa that spills over into the pool. When the pump is off the spa water level falls to the pool level. Will placing a back flow valve on the intake side be enough or do I need on on every route to and from the pump?

I will try to attach a picture.

4 lines to the pump.
Main Drain
Skimmer
Cleaner
Spa

3 returns
Main
Spa
Spa Fountain

Thanks for the help.

 

[ajw22]

You need Check Valves on the Return side SPA and SPA FOUNTAIN lines to prevent them back flowing into the pool when the pump is off.

 

[kcautodoc]

You need Check Valves on the Return side SPA and SPA FOUNTAIN lines to prevent them back flowing into the pool when the pump is off.

Thank you. Just to confirm, no backflow preventer is needed on the Spa line side before the pump?

 

[1poolman1]

You need Check Valves on the Return side SPA and SPA FOUNTAIN lines to prevent them back flowing into the pool when the pump is off.

For a check valve in the spa suction line to work to prevent the spa draining, it would also prevent the pump from pulling water from the spa.

 

[kcautodoc]

Perfect. That's exactly what I kept seeing when I would lay it out on paper