Stain keeps coming back

[VinceL]

When we opened our fiberglass pool, we had about 3/4 of the pool surface covered with a stubborn stain that could not be brushed off. After trying a few things to figure out what kind of stain it was, it responded to some vitamin C tablets, so I figured it must be a metal stain. I poured in a container of Stain Free and 24 hours later nearly all the stain was gone. I brought chlorine back up (FC 2.5 with CC 0) and maintained the TA, CH, pH, and CYA at the levels I have used for the past couple of years.

The staining returned. Since this staining is new, it can be brushed off the sides and bottom of the pool. After brushing while the filter is running, the water becomes very cloudy. I thought the filter would pick up the brushed-off stain, and we would have clean water. But, just a few hours after brushing, you can see the stain returning. I dumped in a bottle of Jack's Magic Purple sequestrant. I did not see any change in the water.

I bought some AA, lowered the chlorine, and dumped in the same amount of AA as I had with the Stain Free. It has been a bit over 24 hours since putting in the AA, and there is no sign of the staining going away

The staining looks exactly the same as the original staining. I am totally puzzled as to why the Stain Free eliminated the stain, but the same amount of AA did not.

We have never had staining issues with this pool in the past. I am confused and frustrated.

At this point I am thinking of getting some more Stain Free since it worked the first time. And, then I guess follow up with maintenance doses of Jack's Magic Purple sequestrant.

Can someone help me before I do something rash like drain the pool.

 

[JVTrain]

Long story short. Metals are a long term problem that will not usually clear up after one treatment. It's ongoing treatment. You may have read it already but this article explains in detail: http://www.troublefreepool.com/content/137-metals-in-the-water-and-metal-stains

If you have a source for metals-free water, it's not a bad idea to think about water replacement. Do you know where the metals came from originally?

 

[VinceL]

Long story short. Metals are a long term problem that will not usually clear up after one treatment. It's ongoing treatment. You may have read it already but this article explains in detail: http://www.troublefreepool.com/content/137-metals-in-the-water-and-metal-stains

If you have a source for metals-free water, it's not a bad idea to think about water replacement. Do you know where the metals came from originally?

I've read more articles than I can count about metal staining in pools. I was surprised that our metal stains came back so quickly. The sequestrant instructions talk about weekly application so I was surprised when our stains came back in just a few days.

Our pool is filled with city water. The only thing I can think of is rain water somehow picking up metal around the pool and then draining in to it. This is our first year with staining so something has clearly changed.

Today I read about a product called CULator which is a packet that you put in your filter pump basket. They claim it captures the metal as it flows through you pump. I found a bunch of posts here on TFP about it. It sounds like some people have had success with it and it has not helped others. With the money I've been spending on chemicals, I figure I will give it a try.

 

[JasonLion]

If I read your description correctly, you did not use any sequestrant at all until after the stains reappeared. That can't work. You have to add sequestrant after lifting the stains and before adding chlorine.