Acidity In The Swimming Pool Water..Too Acidic

by Nee
(Lynbrook, New York)

My water was tested and they told me the water has too much acid in it. I now find my liner is getting rust spots on it.

What do I do to lower the acid in the water and how do I get rid of the rust spots on the liner?

Is this unhealthy to swim in?

Thanks for your question Nee

You talking about the pH level of your swimming pool. The pH level ranges from 0 - 14...7 being neutral. Anything 6.9 and under is considered acidic and anything over 7.1 is alkaline.

If your pool water is acidic it will show a low pH level and/or total alkalinity level.

I would suggest getting a Taylor Reagent FAS-DPD K-2006 pool water test kit. It's the one most pool professionals use and the most accurate.

Water Testing Kit..FAQ..Chemistry Testing..Procedures..Balance..Swimming..

You'll probably need to raise both your pH and total alkalinity levels. Here are the links and charts to do that quickly and easily.

Swimming Pool Alkalinity..How To Adjust Your Pool Chemistry & Water Balance

Swimming Pool pH Levels..Chemistry..Alkalinity..Water..Care

Concerning the rust spots on the liner...

If you only have a couple of spots, you can use a sock with commercial Vitamin C tablets in it. Drop the sock on a spot for about 2 - 3 minutes and the stain should start to fade. If the rust stains/spots don't go away after half an hour, try another few minutes with the sock filled with Vitamin C.

If this doesn't work, you might need to go to an asorbic acid treatment. Here's how to do that:

Bring your chlorine down to as close to 0.0 as you can. The chlorine will use use the asorbic acid so you'll need to get the chlorine down as far as it can go.

You can add Polyquat 60 algaecide to avoid getting pool algae while the chlorine is that low.

You'll use about 1/2 to 1lb.of ascorbic acid per 10,000 gal. Try to go on the lighter side to see if the stains come off before adding any more.

With the filter on circulate, pour the asorbic acid around the perimeter of the pool. Allow the water to circulate for 1/2 hour.

Depending on just how extensive the iron stains are, you might need to start using a sequestrant for metals.

If the stains are gone gone with this treatment, keep the filter in circulate mode and add more ascorbic acid where the stains are.

Leave the filter in circulate until all the stains are gone. Add more asorbic acid if needed.

When all of the stains and spots are gone, you can add the sequestering agent for the number of gallons of your pool.

Put the pool filter back on the "FILTER" setting and leave it on 24/7.

This might lower your pH but you can use the above link to adjust that.

Just remember that you'll have the asorbic acid in the pool so when you add the chlorine the acid will soak it up first, then your water. You'll probably go through alot of pool chlorine to re-balance out your pool.

Once the chlorine starts to even out, stabilize, and hold, that means there should not be any more asorbic acid in the pool. Be sure to have the cyanuric acid level in check as well.

Adjust Your Swimming Pool Chlorine..Chemistry..Salt Water Maintenance..Inground

Try to keep you pH level low, around 7.2ppm for time being, then adjust it slowly. And don't shock the pool for at least 2 weeks.

This addresses the issue of rust spots, but not the reason. You might have some metal rust coming through the liner. As the above is a bandage to the problem, you may want to find the real issue and take care of that.

Hope this helps and have a great Summer

Robert