CH Question

[elwood58]

We had our pool resurfaced three years ago. Since then, CH has been on the rise due to our hard water here in the desert. We did a water change this week, of about 85% of the water.

CH is currently sitting at 160, with a Salt Water Pool target of 250. I hate to add Calcium, as the CH will climb on its own. What are the impacts of leaving my CH to climb on its own?

 

[JasonLion]

You need to adjust TA and or PH up a little bit to compensate for the low CH level. This is the same as when CH is high, you lower TA and or PH to compensate. To figure out how far they need adjusting you can use the CSI calculator that is part of PoolMath. Aim for a CSI of between -0.5 and +0.3.

 

[jblizzle]

I did the same thing a few years ago, started around CH of 130ppm. I just kept the pH on the higher side and as you replace water from evaporation, the CH is going to climb. I think I am approaching 500ppm now after a couple years.

 

[duraleigh]

How long will it take to get above 250? Probably not a problem but see where it is in 30 days. If it looks like it'll take 6 months, that's longer than I would like to be below normal

 

[jblizzle]

FYI, here is how my CH tests generally looked:
4/2013 130ppm
9/2013 250ppm
5/2014 320ppm
9/2014 400ppm
3/2015 450ppm

I figure next spring I might replace bunch of water to lower it back down ... so I am on about a 3 year schedule to keep the CH reasonable, probably could push it to 4 years if I added pH automation (I don't test often enough )