This should be done at the valve that controls whether water is directed toward the spa or pool, not but inserting fittings in the returns.

Scott

Yes, ordinarily that is correct however this is an unusual pool/spa arrangement. The spa is significantly higher than the pool and I want to use the most efficient speed on my intelliflo that I can. The return water won't reach spa height unless the speed is much higher than I like.

The pool is 16000 gals and uses 3 inch suction and 2.5 inch return lines with 5 pool outlets. My thinking is if I plug one or two of the returns (or just reduce its diameter) I can raise the water using the same pump speed enough to reach the spa valve. I have some rubber stoppers to experiment with but eventually want to use something more secure and permanent.

You still haven justified not doing it with the valve at the pad.

Scott