Hello everyone! I have read everything I can find on this forum and elsewhere (though this forum is the most helpful) about acid requirements for a newly plastered pool. Mine seems off the rails, so I'd like some opinions.
I have a 13,000 gallon in ground plaster pool with one waterfall from the spa into the pool, which is the main inflow from the filter. The pool was renovated, including new plaster and waterline tile by a reputable local company, finishing the job on 1-16-25. The plaster used was NPT Stonescapes Aquacool regular pebble. It was applied over a good solid existing plaster after they did some other things to prepare it like bond coat, etc. They did a 6 week acid startup, said that everything was balanced and handed it over to my pool maintenance guys. My guys started their weekly visits, and I had no reason to think anything was wrong. That was a mistake. After 3 weeks of this, with reports saying that the pH was 8, I noticed snow-like stuff all over the bottom of the pool. I skimmed some of it out and found out that it was calcium crystals. 1.5 gallons of calcium crystals. Turns out that the pH was not 8, but over 8. WAY OVER 8 and NEVER was brought down - by the pool company guy during startup or my water guy. Maybe I shouldn't blame them, because I don't think anyone would have expected this. Thank goodness that no one was swimming in the pool yet, because when I put my hand in the pool, my skin was slick like when you get ammonia on your skin. I can't imagine what the true pH was. I called the pool company project manager, who by this time, I had a reasonable relationship with, and he came right over. There was obviously scaling, and so we had to do an urgent low pH acid descaling, which luckily was successful cosmetically. If anything, it looks better because it took a little more of the plaster off the aggregate and it now looks just like the samples. After re-balancing the chemistry, I tested the water twice DAILY, and am still doing this.
We are now 5.5 months out from the original finish date of the plastering and when I check the pH daily at 1130, it has been anywhere from 8.0 to 8.5. I have added anywhere from 16 to 24 ounces of 31.45% muriatic acid daily at that time, and by mid afternoon the pH is 7.4 to 7.6. This repeats daily. EVERY DAY. The amount is calculated either by Poolmath app or the acid demand test in the Taylor kit. I'm holding the alkalinity at around 60 in an attempt to keep the pH from climbing any more than it is. CYA and Cl are fine. Believe it or not, CSI is right near where it needs to be, although obviously it bounces around the target up and down daily. I'm using a Taylor test kit.
So, at this point, the pool is useable and looks great, but the amount of acid I'm having to use is INSANE. Also, my Ca hardness has been climbing slowly with all this what I assume is calcium hydroxide being released into solution. The Ca hardness is now 575. I'm shocked that the CSI can be normal with this level of hardness. Oh yea, also, there is very little plaster dust weekly. Very little. I have thrown away my filter cartridge that went through this and replaced it with a new CC150. Pressures stay low.
I know that's a lot of info, but I wanted to try and give all the info I had. We've had the plaster rep who sells the NPT stonescapes out to the pool, and he and the pool company say just keep going and it'll cure eventually - although they admit they haven't seen anything like this before. So, I'm skeptical of their advice. Can someone please tell my what they think about this? Will my pool ever cure? Should I leave the Ca hardness high so less calcium comes out in the water (if I drop the hardness, I assume it'll pull MORE calcium out of the liner)? Is it doomed? HELP!
I have a 13,000 gallon in ground plaster pool with one waterfall from the spa into the pool, which is the main inflow from the filter. The pool was renovated, including new plaster and waterline tile by a reputable local company, finishing the job on 1-16-25. The plaster used was NPT Stonescapes Aquacool regular pebble. It was applied over a good solid existing plaster after they did some other things to prepare it like bond coat, etc. They did a 6 week acid startup, said that everything was balanced and handed it over to my pool maintenance guys. My guys started their weekly visits, and I had no reason to think anything was wrong. That was a mistake. After 3 weeks of this, with reports saying that the pH was 8, I noticed snow-like stuff all over the bottom of the pool. I skimmed some of it out and found out that it was calcium crystals. 1.5 gallons of calcium crystals. Turns out that the pH was not 8, but over 8. WAY OVER 8 and NEVER was brought down - by the pool company guy during startup or my water guy. Maybe I shouldn't blame them, because I don't think anyone would have expected this. Thank goodness that no one was swimming in the pool yet, because when I put my hand in the pool, my skin was slick like when you get ammonia on your skin. I can't imagine what the true pH was. I called the pool company project manager, who by this time, I had a reasonable relationship with, and he came right over. There was obviously scaling, and so we had to do an urgent low pH acid descaling, which luckily was successful cosmetically. If anything, it looks better because it took a little more of the plaster off the aggregate and it now looks just like the samples. After re-balancing the chemistry, I tested the water twice DAILY, and am still doing this.
We are now 5.5 months out from the original finish date of the plastering and when I check the pH daily at 1130, it has been anywhere from 8.0 to 8.5. I have added anywhere from 16 to 24 ounces of 31.45% muriatic acid daily at that time, and by mid afternoon the pH is 7.4 to 7.6. This repeats daily. EVERY DAY. The amount is calculated either by Poolmath app or the acid demand test in the Taylor kit. I'm holding the alkalinity at around 60 in an attempt to keep the pH from climbing any more than it is. CYA and Cl are fine. Believe it or not, CSI is right near where it needs to be, although obviously it bounces around the target up and down daily. I'm using a Taylor test kit.
So, at this point, the pool is useable and looks great, but the amount of acid I'm having to use is INSANE. Also, my Ca hardness has been climbing slowly with all this what I assume is calcium hydroxide being released into solution. The Ca hardness is now 575. I'm shocked that the CSI can be normal with this level of hardness. Oh yea, also, there is very little plaster dust weekly. Very little. I have thrown away my filter cartridge that went through this and replaced it with a new CC150. Pressures stay low.
I know that's a lot of info, but I wanted to try and give all the info I had. We've had the plaster rep who sells the NPT stonescapes out to the pool, and he and the pool company say just keep going and it'll cure eventually - although they admit they haven't seen anything like this before. So, I'm skeptical of their advice. Can someone please tell my what they think about this? Will my pool ever cure? Should I leave the Ca hardness high so less calcium comes out in the water (if I drop the hardness, I assume it'll pull MORE calcium out of the liner)? Is it doomed? HELP!
