Something has been staining my tile grout and cover a greenish color over the past few weeks (see photos), and I can't figure out what the issue is. I'm hoping someone here is more knowledgeable than me and may be able to help.
My ~6K-gallon pool is technically still under construction in Austin, TX. The contractor has a few minor things to do, like replacing a couple coping stones and final inspection, before handing the project over to us. The pool was plastered w/ NPT Tahoe blue mini-pebble plaster and filled on Feb 16. All was well until a few weeks ago when I noticed that the tile grout under the waterline looked green. Then last week, the water level rose during heavy rains, and my automatic cover also stained where the water hit.
Two weeks ago, I had the water tested at Leslie Pools, and the chlorine level exceeded 15ppm. It seemed the maintenance company the contractor had hired to maintain the pool water until construction is completed overdid it with the chlorine perhaps to keep from having to come so frequently for maintenance. I found 5 chlorine tablets in the equipment container and removed them to allow the chlorine level to decrease.
This past weekend, I had the water tested again (see test sheet attachment). The only outliers were free chlorine = 7.89 ppm (still high), pH = 8.1 (possibly due to heavy rains), and copper = 0.2 ppm. I don't know where the copper is coming from, as my newer house has no copper fittings, and the maintenance guy said he has not used any copper-based chemicals. I did test out the pool heater recently just to see if it works and that I could use it; perhaps the copper came from the heater? These chemical findings were in line with my new Taylor test kit and copper testing kit I used to verify, so I think the latest Leslie Pool test is accurate. I also tested my home tap water to compare and found zero copper.
I tried scrubbing sections of the tile and cover with a nylon brush and Dawn dish soap because I figured that if I don't know what's causing the stain then Dawn will at least be a safe/gentle test, but nothing happened. Can anyone help brainstorm what is causing the staining? I feel anxious that my brand new pool is stained after so much time and money spent on the project. I intend on putting my foot down and not accepting the project until the issue is fixed by the contractor, but I'd like to understand why this is happening so I can avoid future stains like this. Thanks for the help!
My ~6K-gallon pool is technically still under construction in Austin, TX. The contractor has a few minor things to do, like replacing a couple coping stones and final inspection, before handing the project over to us. The pool was plastered w/ NPT Tahoe blue mini-pebble plaster and filled on Feb 16. All was well until a few weeks ago when I noticed that the tile grout under the waterline looked green. Then last week, the water level rose during heavy rains, and my automatic cover also stained where the water hit.
Two weeks ago, I had the water tested at Leslie Pools, and the chlorine level exceeded 15ppm. It seemed the maintenance company the contractor had hired to maintain the pool water until construction is completed overdid it with the chlorine perhaps to keep from having to come so frequently for maintenance. I found 5 chlorine tablets in the equipment container and removed them to allow the chlorine level to decrease.
This past weekend, I had the water tested again (see test sheet attachment). The only outliers were free chlorine = 7.89 ppm (still high), pH = 8.1 (possibly due to heavy rains), and copper = 0.2 ppm. I don't know where the copper is coming from, as my newer house has no copper fittings, and the maintenance guy said he has not used any copper-based chemicals. I did test out the pool heater recently just to see if it works and that I could use it; perhaps the copper came from the heater? These chemical findings were in line with my new Taylor test kit and copper testing kit I used to verify, so I think the latest Leslie Pool test is accurate. I also tested my home tap water to compare and found zero copper.
I tried scrubbing sections of the tile and cover with a nylon brush and Dawn dish soap because I figured that if I don't know what's causing the stain then Dawn will at least be a safe/gentle test, but nothing happened. Can anyone help brainstorm what is causing the staining? I feel anxious that my brand new pool is stained after so much time and money spent on the project. I intend on putting my foot down and not accepting the project until the issue is fixed by the contractor, but I'd like to understand why this is happening so I can avoid future stains like this. Thanks for the help!
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Do you happen to have a container of "pH Down" (which is dry acid) laying around? If so, place some of that in a thin sock or nylon and (with gloves on) rub it on the stained tile to see if it does anything.
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