Pool stains not scrubbing off?

[Aleforge]

Since I opened my pool this year I have had some pretty noticeable stains through it its shell (fiberglass). Its kind of a dingy spotty grey color. I have scrubbed the life out of it and it still had not gotten any better. Is there some type of chemical I should add to help dissolve it? I assume not knowing exactly what stained it might make it more difficult to remove. But I was not sure if there is something more universal that might be worth a shot.

Thanks

 

[jobondur]

First you have to determine what type of stain it is. Get yourself some Vitamin C tablets and a chlorine puck. Rub/crush the Vitamin C on the stain for like 30 seconds and see if the stain disappears. If it does, then it's likely a metallic stain. If it doesn't, hold the chlorine puck on the stain and see if it disappears. If it does then it's likely organic. Report your results along with your water chemistry back to the forum and you'll get advice.

 

[pooldv]

Is it raised? Rough? Post a set of test results, recent and from last year might help to diagnose.

 

[Aleforge]

I will do that and give an update. It doesn't seem to be rough, just discolored and not uniform. Its over the entire surface but not a solid color. I never have kept test results before, I check the levels a few times a week. Is that something you guys do?

 

[pooldv]

I usually write down result once a month in a folder to watch for trends.