I have a pool and spa (elevated) combo with one pump and filter for both the pool and the spa. The water has consistently sparkled and I have had zero issues for the past year or or so thanks to TFP.
For the past three years (since I acquired my home) I have been running the SWCG with the valves set to full suction from the pool and return split about 50% to each of the spa and pool. The return to the spa allows for spillover from the spa to the pool and everything gets chlorinated. I like the effect of the spillover, but I have constant pH rise that I believe I can partially slow down by adjusting the valves and schedule programming to eliminate the spillover and the resulting aeration. If I make that adjustment I would need to isolate the spa from the pool and run the SWCG on each at different times in the day and test and balance the pool and spa essentially like thy are two different systems. Is that how most people with pool/spa combos and SWCG manage things? It does not seem efficient, but I am not sure how else to proceed and effectively sanitize both the pool and the spa.
Here are my numbers as of this morning with Taylor Kit:
pH 7.2 (Just added acid last night so pH is on the low side right now)
Alk 70 (I have been lowering regularly from a peak of 135 on 5/13/14)
Any advice is appreciated. Thanks.