Hey guys, I'm a first-time pool owner, and we've had it since December 2016 (construction completed). We've had ongoing issues with high calcium, even though the water source in my town is only 160 CH. I also can't seem to keep the pH at my desired level of a 7.4. These may be two separate issues, but hopefully someone has insight.
It's a 20,000 gallon pool with a spa, and the plaster is Luna Quartz. Let's start with the calcium problems. When it was first built, we had TONS of plaster dust, and the builder gave it two acid baths to try to resolve the problem. Calcium was at a 480 when they ended their complimentary maintenance in March 2017. Over the next two years, we had all kinds of scale and calcium nodules form on the plaster.
This past May (2019), the pool was drained the first time by the builder, and they performed an acid wash to remove the scale and calcium nodules. After refilling, the calcium was still very high and acid wash not properly done. That led to the builder doing an acid bath and draining it again in June. Upon refilling, the CH was tested at 160 (same as tap water), so I added calcium to bring it to a 220. So far, so good.
By July, just one month after refilling it the second time, I noticed the CH had already climbed to a 320. Given that cal hypo shock contains calcium, I thought possibly the shock was causing the problem. I stopped using cal hypo and switched to liquid chlorine a few weeks ago. The calcium seemed to stay steady at 320 for a couple weeks, but on my last test a few days ago it had climbed to a 350.
The other thing that I cannot seem to keep steady is the pH. Even when the water is perfectly balanced and the LSI is at a 0.00, within a 24 to 48 hours, my pH will go from a 7.4 to 7.8 or 8.0. I'm having to add 4 to 6 cups of muriatic acid almost every other day to keep the pH back down to a 7.4. (The reason for keeping it at a 7.4 is to keep my LSI as close to 0 as possible. At a 7.8 or 8.0, the LSI is at a +0.4, and I'm concerned about having more scale and calcium deposits.)
1. What might be causing my CH to rise?
2. Why can't I keep my pH steady?
Here are my numbers as of today:
Temp: 93 degrees (it's hot in TX right now)
pH: 7.6 (added 6 cups of MA yesterday to bring it down to 7.4, and it's already back up to 7.6)
Alkalinity: 100
CYA: 40
Chlorine: 2.0 (also added about 1/2 gallon of liquid chlorine yesterday, which I know has high pH)
It's a 20,000 gallon pool with a spa, and the plaster is Luna Quartz. Let's start with the calcium problems. When it was first built, we had TONS of plaster dust, and the builder gave it two acid baths to try to resolve the problem. Calcium was at a 480 when they ended their complimentary maintenance in March 2017. Over the next two years, we had all kinds of scale and calcium nodules form on the plaster.
This past May (2019), the pool was drained the first time by the builder, and they performed an acid wash to remove the scale and calcium nodules. After refilling, the calcium was still very high and acid wash not properly done. That led to the builder doing an acid bath and draining it again in June. Upon refilling, the CH was tested at 160 (same as tap water), so I added calcium to bring it to a 220. So far, so good.
By July, just one month after refilling it the second time, I noticed the CH had already climbed to a 320. Given that cal hypo shock contains calcium, I thought possibly the shock was causing the problem. I stopped using cal hypo and switched to liquid chlorine a few weeks ago. The calcium seemed to stay steady at 320 for a couple weeks, but on my last test a few days ago it had climbed to a 350.
The other thing that I cannot seem to keep steady is the pH. Even when the water is perfectly balanced and the LSI is at a 0.00, within a 24 to 48 hours, my pH will go from a 7.4 to 7.8 or 8.0. I'm having to add 4 to 6 cups of muriatic acid almost every other day to keep the pH back down to a 7.4. (The reason for keeping it at a 7.4 is to keep my LSI as close to 0 as possible. At a 7.8 or 8.0, the LSI is at a +0.4, and I'm concerned about having more scale and calcium deposits.)
1. What might be causing my CH to rise?
2. Why can't I keep my pH steady?
Here are my numbers as of today:
Temp: 93 degrees (it's hot in TX right now)
pH: 7.6 (added 6 cups of MA yesterday to bring it down to 7.4, and it's already back up to 7.6)
Alkalinity: 100
CYA: 40
Chlorine: 2.0 (also added about 1/2 gallon of liquid chlorine yesterday, which I know has high pH)
