Pool is 16 years old. Was replastered and converted from traditional chlorine to SWG last summer--worked great for a year. With record heat this summer, water temp is 95deg. Several days ago we had a big rainstorm, and the pool started greening up. Took water sample to pool store, added conditioner, acid, stabilizer, yellow out, SuperZappit. Backwashed filter twice.
Things looked better, then green algae returned to the water line, and now there is a very persistent yellow algae in spots on the pool walls.
Latest test results from pool store: FC=0, CC=0, ph=8.2, TA=130, CH=200, CYA=45.
I'm buying way too much chemical from my friendly pool retailer, and this yellow stuff will not scrub off.
Looking forward to your advice!