- Mar 5, 2020
- 3,221
- Pool Size
- 66000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Astral Viron V35
So I think the slowing rising pH from my SWG and the bubbles from the spa pushed it over the edge and brought more Iron out of soln.. but there was enough residual MM to cause a reaction...
Our spa always had ugly stains, came complimentary with house and pool. My theory always was the same as yours, that the bubbles in the spa brought pH in the spa much higher than in the pool, resulting in stains only in the spa. Last week I finally tested a spot with a vitamin C tablet, and it removed the staining. On the weekend, I did an AA treatment of the spa only, stains came out nicely. Since I only treated the spa, I just dumped the water afterwards. Ordered an iron test kit to see if that really was just an old stain, or if there still is iron in the water.