Thanks, I realize now that I have two options: 1. recirculate the water through the spa only; 2. recirculate the spa water through the pool (the equivalent of a spillover tub). I suppose that in the latter case the organic deposits into the spa will be greatly diluted, but it will take longer to bring the spa to temperature, and I will have to control carefully the flow through the tub or it may never reach temperature.

Any other opinions?