How to clean worm stains from pool plaster?

[miles267]

Unfortunately, like many places, we’ve had significant rain. Has resulted in excess works in pool. Haven’t allowed them to sit for very long on the bottom. Luckily have been able to vacuum, scoop and scrape them from plaster quartz bottom surface though there are a few areas where they’ve left faint, brownish stains.

Can anyone recommend a way to clean these stains without having to drain the pool? Have SCUBA equipment, so can swim to bottom with a brush if necessary. Not sure how I can apply chemicals this way if at all.

Appreciate any suggestions. Thanks.

 

[JamesW]

The stains should go away in a few days with slightly elevated fc levels and brushing.

 

[miles267]

The stains should go away in a few days with slightly elevated fc levels and brushing.

Thanks JamesW. I generally keep my FC level at around 6-7 ppm. Would it help for me to go higher? Any spec target?

My current CYA has gone down to 5.0 ppm so a high FC wouldn’t last very long.

 

[JamesW]

Normal to slightly elevated fc levels should remove the stains in a few days.

 

[DeanP66]

Another option is to take a chlorine tablet and rub it on the stains and it should lighten up pretty quickly. That scuba equipment would definitely come in handy for that. That's the only thing I use chlorine tablets for, the occasional organic stain that shows up. It clears up fast.

 

[duraleigh]

My current CYA has gone down to 5.0 ppm so a high FC wouldn’t last very long.

CYA tests start at 20 ppm so not sure how you got 5.0 ppm

Regardless, raise your CYA to 40-50 in anticipation of warm weather and then run your FC about 10 ppm or so.....brushing every couple of days on the stains and they'll go away. If you have just a very few stains, then DeanP66 has a good idea with the tabs. I am guessing you have a lot so the elevated chlorine will be less work.

 

[miles267]

Thanks Duraleigh. Sorry, yes, my CYA is 50 ppm. My error.

Don’’t have a lot of stains, but a few spots that I’’ve noticed. What tabs would you use? Else I’’ll raise my FC to 10 and brush for a few days.

 

[DeanP66]

I just buy a couple of single tablets from Walmart and keep them on hand. They're the 3" ones, about the size of a hockey puck.

 

[JamesW]

I would just give it a few days. It should resolve on its own.

Tabs can be more trouble than they're worth. The chlorine dust can get on things and cause problems.

 

[duraleigh]

+1 what Dean said

 

[Swampwoman]

If for any reason after a few days the stains don't resolve and appear orange-ish (eg. From the iron in decomposition) since you have gear you could also use a bit of granular ascorbic acid (vit c) in a dishwashing wand right on the stain. But wait and see...if its mostly organic it will likely resolve without doing anything.

 

[DeanP66]

Nice idea Swampwoman, I hadn't thought of that. That's also a good option for spot treatment.

 

[Swampwoman]

^yes, that's my "go-to" metal spot treatment...but I only have a mask and snorkel so have to hold my breath

To the OP, if you end up needing to do the wand approach, I neglected to mention that I mix the ascorbic acid powder about 50 percent with water to ensure it flows when I press the sponge part against the stain.

 

[miles267]

Thank you all SO much for the ingenious solutions. I’m starting w FC. Will resort to ascorbic acid when the season starts and the water is warm enough. I’m not brave enough to throw on a wet suit this early! [emoji28]

 

[miles267]

Sorry failed to ask - is there a pref between powder or crystals?

 

[Swampwoman]

I'm not sure that it matters. I just use from some a little 1 or 2 lb bulk bag I got on Amazon.