This is my first time posting but have been reading and using suggestions from here since we opened our pool 3 years ago. I use the TF-100 test kit since day one.
This is our third year with our pool. We have a swg, 16x32 vinyl on ground pool, 13,400 gal approximately. Just recently we noticed brown stains on the bottom of the pool. We tried a chlorine tab on the bottom over the weekend and it seemed to help but they are starting to return. Numbers yesterday were:
These numbers have been fairly consistent since we have had the pool. This year at opening I had a hard time getting (just waiting) for the TC to drop down. At opening it was 14, a week later it was 15. We turned down the swg and brought it down to 7, turned it down more and had it at 4. We were going out of town and didn't want issues so turned it up a bit, when we came back a week later it was 8. Just checked it tonight TC is 5.5, plan on checking in the morning for loss and see what that tells me. In the mean time I am trying to figure it out. It's making me crazy! For 3 summers I have had beautiful clear water with very little effort. My husband keeps saying brown algae but my CC is 0. He has also suggested that it maybe coming from under the liner. Thoughts or suggestions please.
16x32' 3.5' depth, vinyl liner, swg, Hayward sand filter and pump, Southern Maryland area.