Circulate Separate Spa and pool with 1 pump ?


LifeTime Supporter
Jun 17, 2010
Glendale, CA
First off - Thanks for this forum. Has helped tremendously.

Have a pool/spa that has seen many years of neglect. Looking to rehab a bit, but am tight on budget as the rest of the house is messed up as well.

The Pool and the Spa are physically separate. The Spa is elevated about 4'

Currently plumbing setup at pad is painfully simple. Single Pool Suction Pipe, Single Spa Suction - with a Jandy 3 way to 1 Pump. Single Pool Return and Single Spa Return - with a Jandy 3 way.

I'm looking for a simple(ish) way to get some circulation between the spa and the pool to help with chemicals, etc. Obviously my issue is I constantly lose water from the spa to the pool when I attempt to circulate.

If I were to install a spa bypass line on both the return side and the suction side with the appropriate check valves I could theoretically adjust the flow of the bypass lines to maintain level in the spa and get come circulation and not lose level when the system is shut off.

I can't find any examples of a suction side bypass line which makes me think it's uncommon/incorrect. 1 concern I have is debris in the suction side pool check valve sticking it open - causing the spa to drain when the system shuts off and then suck air the next day when everyone is gone.

Any thoughts


TFP Expert
Platinum Supporter
LifeTime Supporter
May 7, 2007
Silver Spring, MD
Welcome to TFP!

You can't maintain the spa water level in such a system without either always turning both valves at once to full on/off positions, or some kind of float valve or overflow drain on the spa. Once you allow mixing of the pool and spa water, the spa inflow rate and the spa outflow rate can never be balanced exactly. No matter how close you got the flow rate, there would always be some error and the spa will either drain or overflow.


LifeTime Supporter
Jun 17, 2010
Glendale, CA
Ah the vast gulf between theory and practice. I've gotten it to work for a pumping cycle, but of course 2 weeks is another story. Will plan on adding a spa overflow when we get to the big pool renovation.

Thanks for taking the time and helping us reclaim our green monster.


Well-known member
Jul 8, 2008
Dallas, Tx
I have a very similar set up, except, and I think this may be key, my spa is not elevated. I have a Jandy 3 way on the suction side, and a Jandy 3 way return. I circulate both pool and spa together successfully. It took some adjusting to get the valves positioned just right, and it isn’t exactly balanced- it will either drain a little or fill a little, but not so much that there is a problem before the system shuts off.

However, once the system shuts off the water seeks a level between the pool and spa- if the spa has drained a little during the filter cycle, it fills back up- or drains down if it filled during the cycle. Your spa, being raised, is going to drain into the pool once the equipment shuts off. If you could find a way to keep the water from back flowing through the open system I bet you could make it work, though it would probably take some minor tweaking of the water levels over time since it won’t be able to re-level itself after each filter cycle.