Can't get the chemistry dialed in after 100% water change

Apr 23, 2013
23
San Diego, CA
My Calcium Hardness had climbed up to 650ppm from 450ppm back in Aug 2012. That's about 10ppm/month.
I did a 100% water change on April 19th, 2014.

DATE 04/17/2014 (Before Water Change)
Water Temp: 72
FC: 5.0
CC: 0.0
PH: 7.6
TA: 60
CH: 650
CyA: 35
Salt: 2700
Balance: 0.2

DATE 05/15/2014 (1 month after water change)
Water Temp: 80
FC: 7.0
CC: 0.0
PH: 7.5
TA: 125
CH: 210
CyA: 70
Salt: 2700
Balance: 0.0 (Watergram)
CSI: -.24 (pool calculator)

I'm having a couple problems:
1. The TA is high, I'd like to get that down to around 70
2. The pool is taking alot of muriatic acid (about 1.5 pints a day) to keep the PH in check
3. The CH is below 250 but will climb 10ppm each month, so that will self correct in 4 months.

I don't know why the pool is taking so much acid to keep the PH at 7.5 I know the chlorinator will cause the PH to rise, but my chlorine generator is set to 70% right now. It runs 3 hrs/day at 2500RPM and 3 hrs/day at 1000 rpm. It's making more chlorine than I need right now, so maybe I just need to reduce the run time. It has been over 100*F here over the last couple days, so I was reluctant to turn it down to much.

You guys have any thoughts on how to deal with this? Thanks.
 
1. The TA is the last thing to worry about after everything else is running smooth and you are bored
2. SWGs do that, coupled with the higher TA ... keep the pH in check and the TA will lower itself
3. I left mine at 130ppm knowing that it would climb as well ... no issues.

Lower the % if your FC is higher than needed, that will also slow the pH rise.

I think your title was a bit overly alarmist ... things look pretty good to me ;)
 
Ok, I appreciate the insight.

I will just monitor the TA and see if it goes down on its own.
I will let the PH rise to 7.7 and keep it there.
I will lower the chlorinator to 60% and see how that works out.

I'll give it a couple weeks and let you know how it worked out.
Thanks again.
 
Your fill water is no doubt adding TA if it's adding CH. So every time you top off, you're raising TA. It will be an endless battle. Just get used to dumping a lot of acid in. Every pool has its own appetite. I have learned that every inch of water I add, I need about a cup of MA. So I just add it to the hose stream when I'm filling.

If you run the spa full tilt, you'll drive pH up really fast. It's good to know if you're trying to lower TA by acid and aeration, but if you're not, it's a PITA. I reduced the flow to my spa to a slow trickle out the spillway and I stuck an old paint can cap over the air intake to minimize the bubbling. It helped some.
 
I'll give it another month and see where its at. Hopefully the TA and CH will slowly self correct over time.
I try to adjust the chlorinator to keep the FC at 5.0ppm.

I'm not real worried about it; I just wanted to get some outside input from the experts. I don't bother asking the pool store any more. I just come here.

The water looks great right now. We'll see how it goes.
 
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