Calcium hardness level after acid bath

[Cyclist7531]

We decided to let the Pb do an acid bath to resolve an issue we were having with our quartz plaster pool. So far the treatment has had a positive effect however since the acid bath a few weeks ago the CH has risen from around 250 to a stable 650. My total alkalinity has stabilized at around 80 and my PH is at 7.6. Water temp is 58, CYA is 30. We are still using liquid chlorine and have not added any salt to the pool for the SWG. FC is at 3. According to Pool Math my CSI is 0.08. Fill water has a CH of 275. Being my CSI is within target should I leave the CH alone or should I drain some out and replace?
Also I assume as our temps warm and the pool is used there will be a natural replace ment of water which would bring the CH number down. Is that a correct assumption?
Thanks

 

[Texas Splash]

You're right on all counts. Once the acid treatment was completed, the calcium became soluble which is why the water's CH content spiked. You'll have to watch the CSI now to ensure it doesn't try to revert back to the walls. Try to adjust any of the items in your control (CH, pH, TA) to keep the CSI only slightly negative. Of course exchanging some water might help, but you have a healthy CH content in your local water too (275). Regardless, a CH of 600 is still very manageable if you contain the pH and TA, especially as water temps increase this season. I would look-forward to other ways add fresh water this year (i.e. rain gutter spout containment, water softener supplement, using a cover to reduce evaporation, etc).

 

[Cyclist7531]

Thanks. I’ll keep an eye on the levels. I do have a water softener hooked up to the house water (it’s not connected to the pool auto fill). When I need to add water should I use the soft water then temporarily?

 

[Texas Splash]

When I need to add water should I use the soft water then temporarily?

You certainly can from time to time. Every little bit should help. Keep in mind periodic additions are probably no big deal. Excessive refills from a standard home water softener may wear-out your unit's internal resin bed faster than normal. I actually installed a separate "out" line from my water softener just to have a separate spigot out back for a hose whenever I felt like adding some soft water.

 

[Cyclist7531]

Thanks. I have a separate spigot outside as well that I can tap for soft water. For now I’ll keep an eye on my water chemistry and when a need to add water to top off the pool I’ll use the soft water and then monitor my CH to see if it’s going down.

 

[Brett S]

One thing to keep in mind is that calcium doesn’t evaporate. So if you’re losing water due to evaporation then the CH level in the pool will slowly go up as the water level goes down. If you top off the pool with water that has any calcium in it at all then your CH will continue going up. If you use softened water with no calcium in it to top off the pool then it will keep the CH level stable.

However if you lose water due to splashing and run off from the rain, then calcium will exit with that water and by topping off with softened water then you will be able to (very slowly) lower the CH level.

 

[Cyclist7531]

Thanks. Maybe I should then drop the water about 6” or so and refill with the soft water to see what that buys me and then go from there

 

[markayash]

We decided to let the Pb do an acid bath to resolve an issue we were having with our quartz plaster pool. So far the treatment has had a positive effect however since the acid bath a few weeks ago the CH has risen from around 250 to a stable 650. My total alkalinity has stabilized at around 80 and my PH is at 7.6. Water temp is 58, CYA is 30. We are still using liquid chlorine and have not added any salt to the pool for the SWG. FC is at 3. According to Pool Math my CSI is 0.08. Fill water has a CH of 275. Being my CSI is within target should I leave the CH alone or should I drain some out and replace?
Also I assume as our temps warm and the pool is used there will be a natural replace ment of water which would bring the CH number down. Is that a correct assumption?
Thanks

They had to acid wash mine but PB argued for 3 months blaming my chemicals.
From reading the post here it seems common

 

[Sandi DC]

I had a pool installed last October and also had to have an acid bath done due to a poorly executed initial acid wash leaving lots of streaks in the pool where the aggregate didn't surface. This sounds like a possible solution to us currently wondering how our calcium level got to a level of 600. So.. the acid bath consisted of 7 gallons of MA being circulated through our pool using a small submersible pump and hose for 3 or 4 days. Does that mean that MA increases calcium levels in the pool? My PH has consistently risen again and again back up to 8 so I keep putting MA in the pool to lower it.

 

[markayash]

My Pool guy wanted me to add 5 gallons and it was already around 6.8 and use the regular pump and I refused..He finally drained and acid washed