Staining

Steve Bibb

Silver Supporter
Apr 6, 2019
2
Prattville, AL
Hi all. First post. I love the community here at TFP. I have been reading and learning here for about 2 years. We got our pool in 2014, and my wife took care of it, using the pool store. Things got crazy in the spring on 2019, and that is when I found this site. I started taking care of the pool, and we quit using pool store advice or testing.

In 2019 the pool was stained and my wife had used pool shock with copper in the past. During out fight with stains in the spring on 2019, we added citric acid, but we didn't remove the metals from the pool. That year, I had to add acid regularly to keep the pH down. I noticed that when the pH got to about 7.8 the stains would start to reappear. Over the winter on 2019, we got a lot of rain, and it diluted the pool water. The summer on 2020, the pool was super easy to maintain. I didn't have to add acid at all. In fact, the pH stayed at the low end (around 7.2).

This winter I haven't done much to the pool. I have noticed that the skimmer baskets have gotten that brown stain that we have had before, and the vinyl liner is showing the yellowish stain that we had before. I did all the pool tests today, expecting to find high pH, but was surprised to find it about 7.3. Here are my test results:
FC - 2
pH - 7.3
TA - 50
CYA - 50
salt - 2600 ppm
temp - 52F

I know the salt, chlorine and CYA is low. I don't normally add chemicals over the winter because of the rain overflowing the pool just pours the chemicals down the drain. I plan to add salt once it warms up some, that try to get chlorine in the pool before the algae gets me.

So this is a long intro to the question. What do I need to do to get rid of the staining? Is it copper from the shock from 2 years ago and before?

We use city water to fill the pool. The city water comes from wells. In 2019, when I was fighting the staining, I emailed the water department and was told " Our well has a very low iron content. When we test for iron it is below detection level." I am starting to think that it is iron in our fill water. I just remembered that at the end of last summer, we had a small leak and we added a lot of water for several days.

If it is iron, should I buy some citric acid. I have been reading up on that today. I'm already in a good spot with chlorine and pH. Should I add the citric acid and use the poly fil in my skimmer baskets?

Thanks and sorry for the long post.
 

Texas Splash

Mod Squad
TFP Expert
LifeTime Supporter
Welcome to TFP! :wave: While you probably have some copper in the water from previous store products, it's clear you also have iron as well since the citric acid helped. You may have a metals cocktail going on. It is odd that you are seeing staining now that your pH and FC are so low, but perhaps the iron content just increased too much over time. With either type of metal, we know it isn't going anywhere unless you can replace the water with fresh water. That's especially true for copper. Sometimes iron can be reduced by filtering through some polyfill over a period of time. While we generally don't advise store testing, you might consider taking a sample anyways just to see what copper and iron level they show. It might help confirm what actions is more appropriate at this point.
 

Steve Bibb

Silver Supporter
Apr 6, 2019
2
Prattville, AL
Thanks for your quick reply. We haven't taken a sample to the pool store in a long time. I think during the summer of 2019 we took a sample and they didn't detect any metals, but we knew we had metals because the citric acid worked. We will take a sample again, and see what they say. I just put some polyfil in the skimmer basket, with a skimmer basket sock. We may give the citric acid another shot. Thanks.
 

Texas Splash

Mod Squad
TFP Expert
LifeTime Supporter
Here's an interesting story that you might find helpful for iron removal.

 
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