Okay, I have been working my way through problems with my inherited pool (bought house last year). So far, I have properly shocked the pool (1 month ago). OCLT tests since have been perfect. I am reasonably confident there is no bio in the pool. I solved an FC loss problem (attributed to AA treatments). Now it is on to the staining problem.
I have terrible yellow-brown staining that begins on the steps (plastic) and quickly spreads to the vinyl liner (see picture below). This process takes a couple of days once it really gets going. Here is what I know. AA treatments work like a charm. It will take the pool to crystal clear in about 1/2 hour. This will last roughly a week before the stains start to set in again. Now here comes the strange part. I went to get a metals test at the pool store today. My iron is essentially zero, by my copper is high at 0.8.
Source of the copper?? Not sure. I am using 2 oz of copper based algaecide a month. Perhaps that adds to the trouble. Also, the previous owners used chlorine pucks instead of the SWG cell (they were too cheap to fix the computer that runs the cell). I have read that this may increase copper. ??
Anyway, the schmo at the pool store also suggested Tannic Acid. Tannic Acid is possible since we have a lot of oak trees by the pool. But we have a screened in porch, so less bio mass gets into the pool than most...but still could be a problem. AND high FC does not wipe out the stains. I have been up to 10-15 ppm with FC and the stains don't budge one iota. Incidentally, direct chlorine application to the stain does nothing as well.
I read up on both iron and copper trouble via this forum. I have many conflicting signals on this one. Not sure which way to go. If I can't find a reasonable solution to the problem I am thinking about dumping the pool water and starting fresh.
What do you think???
Here are the other vitals via TF-100
SWG (T-cell 15)
CC 0.0 - 0.5
* I have been really diligent on these numbers. I kick them back into line as soon as they depart normal.