Is this copper staining?

Wilderpa95

Silver Supporter
Apr 15, 2020
9
Georgia
First, a thank you.....I have been a pool fool for years, blindly doing whatever the local pool store told us to do. I discovered your site last Fall and am a total convert! Just finished our first ever SLAM with $50 worth of liquid chlorine as compared to the $2-300 we usually spent on chemicals recommended by the pool store each Spring. So a BIG thank you. If we manage to keep our jobs during the pandemic, we will be sending in a donation later this month. Now my question. For several years we have been plagued with brownish reddish staining of our steps and liner. Based on some research last year, we learned it could be copper, so we disconnected our heater and went through a successful polyquat/ascorbic acid/Jack’s Magic/C-U-lator process to clean it up. But, the staining is now back again this year. Tested water for copper (LaMotte Copper test kit) and results are zero copper in the water. However, testing with Vitamin C tablets shows complete removal of the stain in just 60 seconds which I thought means it is copper. I have attached some pictures taken during the Vitamin C testing. Any thoughts on what the stain could be? We have a massive oak tree and many pine trees around our pool. i know these can cause staining, but would Vitamin C clear it up?
 

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JoyfulNoise

TFP Expert
Platinum Supporter
May 23, 2015
17,216
Tucson, AZ
It’s iron, not copper. Vitamin C would make a copper stain turn darker. Vitamin C doesn’t usually lift tannin stains (oak tree), chlorine will do that.

Are you on a well or city water? Either way, you have iron in your water.
 

Wilderpa95

Silver Supporter
Apr 15, 2020
9
Georgia
We live in Georgia where the soil is red from iron oxides, so it would make sense that we have iron staining, but I'm still confused as to why the Vitamin C removes it.
 

ajw22

Gold Supporter
TFP Guide
Jul 21, 2013
19,398
Northern NJ
We live in Georgia where the soil is red from iron oxides, so it would make sense that we have iron staining, but I'm still confused as to why the Vitamin C removes it.
Vitamin C is ascorbic acid which is a mild acid that converts iron staining into dissolved iron in the water. You then have to bind the iron to a sequestrant or replace the water with metal free water.