Constant Staining In Salt Water Fiberglass Pool

[mbecher]

Help!!! I'm so tired of the stains in my pool!

I had a fiberglass pool (salt water) installed 4 years ago, with an aqualogic chlorinator. It wasn't installed until the end of the summer, so it was closed up shortly after it was finished. When the pool was opened the next summer (we live in New Jersey), the water was clear - just some leaves on the bottom, which cleaned up real well. After about one month, I started seeing stains on the bottom and sides of the pool. They are a grayish-yellow color. I had the water tested for metals, but there never was a significant amount. The pool guy told me to use a stain and scale product, which I did. The stains started to fade, but after awhile, I noticed that my chlorine reading was always very low (0-.5). With this being my first real summer using the pool, I thought my chlorinator wasn't working, so I called Goldline. They told me to test my phosphates, which I did and found they were sky high - over 2000. They said this was my problem - that the phosphates should be close to 0. So the rest of that summer, I used Phosfree and got my phosphates down. The Natural Chemistry people were very friendly and helped me out a lot, except my pool didn't cooperate. I did what they said, using their stain free product to get rid of the stains, then metal free as a maintenance. The stainfree did remove the stains, and I used the metal free, but after a few weeks, the stains came back. I keep the PH at around 7.4, and Alkalinity around 120. Last summer I tried Jack's Magic Purple Stuff - and still have stains. The guys who opened the pool this summer recommened Bio Dex, but I haven't tried it yet. I see a lot of posts on this forum about stains, so I figured the best place to get answers is here.

Which stain product should I use and what do I do to keep the stains away? Do I need to worry about phosphates with a salt generator (my pool has never been green) Please help! I'm really trying to understand all of this. Is it possible to have a salt water fiberglass pool without stains?

Thanks so much.

[pooltech9]

My NJ fiberglass pool has no stains. Phosphates eat up your chlorine faster than your cell can produce it. I also found out that some municipalities have phosphates in their city water as it preserves the integrity of the piping. I found this to be so in a pool in Fairfield, NJ that had a leak and an auto-fill. If you have been adding water you may be adding phosphates. Test your tap water. A phosphate test kit is about 8 bucks. You are testing in parts per billion, not parts per million. They should be zero in your pool but the cell will work fine up to 125ppb phosphates.