New pool owner, pH keeps going up

[Kemyst]

I have cut all ties with my pool shop after getting a ton of misleading advice (& unnecessary products!) from my pool shop. Pool shop suggested I use CYA-free shock, as I had 100ppm CYA. I now have high CH with all the cal hypo I've thrown in. I've switched to the TFPC method & I seem to be adding a lot of muriatic acid to keep the pH stable, around 12-15oz / 2days to keep pH @ 7.4-7.6.

Pool chem results are:

PH 7.6
FC 3.0
CYA 30
CH 450
TA 100
Temp: 92
Size: 18,000 gal

Is this a typical amount of acid? Do I have something else wrong?

 

[YippeeSkippy]

Your CH isn't enormously high....Your TA is a tad high but repeated doses of MA will work on lowering that. But do you have any fountains or other doo-dads that are providing a lot of aeration which causes the pH to rise? As you lower your pH, the TA will lower and after a few weeks it may all stabilize

 

[DaninFLA]

12-15 ounces every two days isn't bad. that's probably what I add on average and my pool is 1/2 your size. your bigger issue is your CYA, need to lower that. only way to do that is drain/refill. that would solve your CYA issue, your CH issue and also probably reduce your TA some which is making your pH rise

 

[1stand3rd]

DaninFla, his CYA is only 30. Level is OK. Are you confusing it with another number?

 

[Kemyst]

I've been adding 3" pucks to get my CYA up from 20ppm. Rain in Texas took my high CYA from 80 -> 20 just through dilution in Spring. No water bill to fix that

Should I stop adding the pucks now that CYA 30ppm?

 

[bigglesworth]

Welcome to the forum Kemyst. I'm adding about the same amount to my water every 2 days. I have a spillover on the spa, so I'm thinking that's probably the major cause for me. My TA is at 70. As far as I can tell your numbers look great. I wouldn't worry about the CH. Mine is hovering around 700. Just use poolmath to keep your CSI in range.

Every pool is different, so it may be normal for yours to use 12oz/2 days of MA (I don't think it's completely abnormal anyway).

 

[DaninFLA]

DaninFla, his CYA is only 30. Level is OK. Are you confusing it with another number?

yep. I misread, I see he HAD 100ppm but now its 30ppm. good deal.


- - - Updated - - -

Every pool is different, so it may be normal for yours to use 12oz/2 days of MA (I don't think it's completely abnormal anyway).

totally agree, that amount does not seem overly excessive at all. 12 oz every 2 days means 1 gallon of MA should last about 20 days or so, so 1.5 gallons a month. or $10 worth.

your TA is a bit high which is causing your pH to rise faster. when you lower your pH, lower it to 7.2, not 7.4, etc. this process of going to 7.2, then raising and lowering again will lower your TA. eventually as your TA goes lower, your pH rise will decrease which will mean less MA being used, and less often

 

[Kemyst]

I've been setting TA to 100 as per pool shop, so that was mistake #1. It will drift lower to 90 with the next rainfall, so mother nature should take care of that one for me. Good to know my muriatic consumption is not crazy. I only needed ~ 3-6oz / 2 days when using cal-hypo, so the 4x increase was concerning. Good thing now is that my chlorine bill is 75% less now I'm on 10% bleach from Home Depot.

Thanks for the advice