Pool Stain help

[Scope]

This has been a six+ month issue and could really use some expert help with this one. Pool is 4 years old. Discovered a stain that I believed to be a rebar bleed. Pool store told me to drop a sock of vitamin C pills on spot to see what happens. Spot got larger and much darker. Called my pool builder. He drained pool, cut out plaster and found rusty rebar. He repaired and did an acid wash on pool. Our pool plaster has never been even, so I think he tried to do the acid wash to help with that. We refilled and balanced the pool. Although he fixed the stain, their was a larger stain left from the "sock". Went to pool store and they told me to sink another sock of "lo and slow" in pool to see if their was a reaction. I do not usually use low and slow but use muratic acid. Unfortunately now I not only have the "sock shadow" from the previous issue, but now a 10 foot long streak from the stain to the drain! Upset I went to another pool store--I know--I ordered my test kit today--. She told me to try vitamin c again. I did and where this sock was, the stain is even darker! Not sure what to do other that resurface. Called the people at Jack's magic and they said that I have exposed more aggregate and I needed to sand the surface. They also said I should start adding 2qt. of Purple Stuff and then 16oz. weekly after that to control metals in water.

Any ideas??

FC 4
TC 4
Salt 2900
CH 210
CYA 60
TA 110
Ph 8 from pool store. I did add 1/2 gal. of muratic before this last vitamin c "test"
Phospates 200
Copper .3
Iron .3

 

[zea3]

Hi, welcome to TFP! Try lowering the pH to 7.2 and see if the stain fades. Do you know how the metals got into your water? Do you use well water to fill and top off the pool?

 

[Scope]

City water. Also have been stupidly using an algaecide (Bioguard backup) which I now know contains Copper. Only thing I can think of about the metals is that last summer our pool flooded with red clay because of a new build across the street. New homeowner had covered all the storm drains in the neighborhood to protect our neighborhood pond from sediment. Pool was drained and cleaned at that time as well. Filter sand was also changed. Not sure if that has anything to do with the metals or not.

 

[zea3]

If you used a copper based algacide then that is where the copper came from. Not sure about the iron, could be washed in from the lawn if you use any fertilizers containing iron or minerals. Since your stain does not like the vitamin C it is probably a copper stain. Lowering the pH should help. As long as you have metals in the water you will need to use sequestrant on a regular basis to keep the stains from worsening or recurring. You can take a sample of your tap water and have it tested for metals. If it is metal free it may be best to replace the water with metal free water.

 

[Scope]

Thank you. I will wait for my test kit to come in and then lower ph. A small update. Hubby used a wire pool brush on stain and dark vitamin c stain disappeared. Existing stain did not lighten , but dark vitamin c stain is no longer there. Now I only have stain and long streak from the dry acid.