Whole Pool Stain, Rough Plaster at Season Open

[waterbear]

The difference might be that you did not keep close watch on your pH once you installed the SWG. They have a tendency to cause pH to rise and if you let that happen you could create scaling conditons.

[squirrel49]

During the season I keep a very close watch on my Ph (test daily using Ben's kit) and usually end up adding muratic acid weekly to keep within range.

Ph was 7.4 when I closed last fall. When opened this spring, PH was extremely high (>8.5). I'm not sure what happened over the winter or if Ph rise during the non-operational Winter period is normal or not.

[Lenny]

Same with me. I was all over the PH during the season but it was sky high both times I've opened so far. And Hardness and Alk very low.

I'm still hoping my problem is scaling. But I'm worried that the water pulled calcium from the plaster.

[thomas_CT]

squirrel49. have you heard of a product called hydroquest 100? I read about it but haven't tried it, maybe someone that has can chime in. It's certainly a better alternative than acid wash, imho. And if this application doesn't help your stain problem maybe Ascorbic Acid Powder can. "jus my .02 cents."

[Lenny]

Well, I took a closer look at my steps today. I tried some crushed vitamin C to see what that did to the stains. Not much. But now I believe I have it figured out.

I can see that it's a rough surface on top of the plaster rather than the plaster being pitted. I believe the stains are just scale encapsulated dirt. Does that make sense?

I used a pumice stone and it does work but it's slow and I'd go through an enormous amount of pumice. I'm going to try wet sand paper and see how that goes. Does anyone have recommendations on what would work best for this?

I'm still not sure why this happened and why it's so extensive. It's mostly on the horizontal surfaces. I know that the hardness was low when I opened. Before I closed, the hardness was low and I added a reasonable amount of powder to get the hardness within range. I may have added some after the pump was off and circulated the water with a sump pump and long hose. Is it possible that the calcium not being circulated enough could have caused a problem?

Does anyone know anything about this hydroquest 100? I love to find something that would help reduce the manual work I have ahead of my trying to sand this stuff down.

Thanks,
Lenny

[squirrel49]

Lenny,

I too believe that the condition I have is scale encapsulated dirt. I have tried the pumice stone with just about no luck (a whole stone for very little if any impact).

I am looking at purchasing an air powered underwater orbital sander and diamond pads in an attempt to sand the plaster underwater. I do not want to have to drain and refill this year.

Pat

[ezpool]

Any luck with this? I've been following this thread closely since I'm in the same boat. I closed a perfectly clean pool last winter and opened to a green, algae-filled mess. After cleaning everything up and getting my numbers in line, the water is clear but I've got tan stains throughout the pool. I've super-chlorinated for an extended time and also tried a sequestering agent after 4 lb of ascorbic acid. The stains remain. I've been brushing almost daily with a metal brush but haven't seen a change. I've had some luck with a "Stain Eraser" but that's not an option given the amount of staining. I was wondering if a pressure-washer would help? Anyone tried using a pressure-washer underwater? Will it even work?