New owner of in ground pool with pH/alk problem

Sneauxball

Member
May 1, 2021
8
Montgomery, TX
Pool Size
13280
Surface
Plaster
Hi, thanks for welcoming me to this group. I purchased a new house with existing in ground gunite pool in January, 13280 gal. I’ve read pool care manuals, watched several videos, but I can’t solve this problem: I shock pool with cal hypo, chemistry is great, 3 days later pH and TA creep up, I add 31% muriatic acid to get pH 7.5 and TA 80. After 2 days pH is at 7.8 and TA is 120. If I don’t add more acid at 7.8, pH and TA will go higher. So I add more muriatic acid-volume based on poolmath app. I’m shocking once a week, adding 2 HTH 3 inch chlorine tabs once a week. I just don’t think I should have to add a quart of muriatic acid every 3 days. I’m using Leslie’s 7 in 1 strips. I have trouble deciding the pH with these, so I’m using Clorox pool 3 way liquid test kit for pH. I find the Clorox results for FC and pH are too similar at the different levels, but I’m able to get results in sunshine. My results:

After shock and muriatic acid:
CH 250
TC 5
FC 5
pH 7.2
TA 80
CYA 30-50

3 days later:
CH 250
TC 3
FC 3
pH 7.8
TA 120
CYA 30-50

All results are stable except pH and TA, which are consistently going up. I have a Jandy CV340 filter using 4 Fitpool cartridge filters 85 sq ft. Replaced them 2 weeks ago, run twice daily for 2 hours. Jandy FloPro pump. Also vacuum twice daily with Polaris 360 vacuum. Is my CH too low? Is this causing my problems? Any help is appreciated!
 

Texas Splash

Mod Squad
TFP Expert
LifeTime Supporter
Jun 22, 2014
30,584
Texas, San Antonio/Marion, South-Central Area
Pool Size
17888
Surface
Fiberglass
Chlorine
Salt Water Generator
SWG Type
CircuPool RJ-45 Plus
Welcome to TFP! :wave: I'm sure we can help you. Here are a few things to get you on track:
1. You have to ditch the test strips. They are horrible preceded only by pool store testing. You need to get your own TF-100 (link in my signature) or Taylor K-2006C test kit That's a priority.
2. Be careful about over-use of cal-hypo. Unless you have extremely soft local water, your CH will shoot-up too fast. Stick with liquid pool chlorine or regular bleach.
3. When a pool is properly maintained, there is no need for weekly shocks to spike the FC level. Consistency and good levels are the name of the game. We'll help, but the test kit is #1.
4. A pH of 7.8 is fine, but if it's shooting up too quickly, you can lower the TA just a little it more to help slow the rise of pH. I wouldn't go any lower than about 60 though.
5. TA should not increase unless you add new water or add something to increase it (i.e. baking soda, soda ash). Test strips may be complicating this issue.
6. Please save/read the link below. It has tons of available info to help you.
7. Don't forget to update your signature and include which test kit you have. If you are on a well, list that as well.
8. Aeration also tends to increase pH, so if you have a waterfall or anything like that, be sure to reduce its use.

We'll do our best to help you, but as you can see, the proper test kit is a must. When you get it, post back a full set of results so we can really get accurate on a fix for your issues.

 
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Sneauxball

Member
May 1, 2021
8
Montgomery, TX
Pool Size
13280
Surface
Plaster
Welcome to TFP! :wave: I'm sure we can help you. Here are a few things to get you on track:
1. You have to ditch the test strips. They are horrible preceded only by pool store testing. You need to get your own TF-100 (link in my signature) or Taylor K-2006C test kit That's a priority.
2. Be careful about over-use of cal-hypo. Unless you have extremely soft local water, your CH will shoot-up too fast. Stick with liquid pool chlorine or regular bleach.
3. When a pool is properly maintained, there is no need for weekly shocks to spike the FC level. Consistency and good levels are the name of the game. We'll help, but the test kit is #1.
4. A pH of 7.8 is fine, but if it's shooting up too quickly, you can lower the TA just a little it more to help slow the rise of pH. I wouldn't go any lower than about 60 though.
5. TA should not increase unless you add new water or add something to increase it (i.e. baking soda, soda ash). Test strips may be complicating this issue.
6. Please save/read the link below. It has tons of available info to help you.
7. Don't forget to update your signature and include which test kit you have. If you are on a well, list that as well.
8. Aeration also tends to increase pH, so if you have a waterfall or anything like that, be sure to reduce its use.

We'll do our best to help you, but as you can see, the proper test kit is a must. When you get it, post back a full set of results so we can really get accurate on a fix for your issues.

Texas Splash, thanks for your advice. I had already ordered a Poolmaster 5 way water chemistry case #22270, it comes tomorrow. Do you like this one? I’m confused about lowering TA. Wouldn’t I add muriatic acid to lower TA? And wouldn’t that also lower pH? Is it possible to lower one and not the other? Also the previous owner used chlorine tabs and he suggested that to us, along with muriatic acid. Do you not like the tabs? I’d rather not have to deal with the bottles of chlorine. And I just bought a lot more because of the shortage. Also I don’t have a waterfall or other aeration. I’ll post my new test kit results tomorrow, thanks so much.
 

Texas Splash

Mod Squad
TFP Expert
LifeTime Supporter
Jun 22, 2014
30,584
Texas, San Antonio/Marion, South-Central Area
Pool Size
17888
Surface
Fiberglass
Chlorine
Salt Water Generator
SWG Type
CircuPool RJ-45 Plus
The Poolmaster is not what we would refer to as one of our recommended kits, but it's better than test strips, so use it for now. About TA, you have to use the acid, but the acid has a most dramatic effect on pH first, and the TA falls in slower increments. That's why we pull the pH down to about 7.2 with acid, then the TA may fall 5-10 ppm at a time. When the pH rises high, use acid again and repeat the process until you are happy wit the TA (probably 60-80 range) to help keep the pH more stable.

Tabs (pucks) contain stabilizer (CYA), and after just a few tabs you find your CYA level reaching a maximum point. That's why they are only safe to use for a short period, after that, it's regular bleach or liquid chlorine (same thing). Those do not have stabilizer in them. Pool builders and pool stores are happy to sell you tabs at $120 a bucket, but don't tell you than in 6 months you'll have to drain your pool because those same tabs increased the CYA too high. Before I got my salt generator, I added chlorine each day for 7 years. Not a big deal, I just took my time and poured slowly. You'll be a pro at this before you know it.
 
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CraigChing

Gold Supporter
Jun 15, 2019
137
Plymouth, Minnesota
Pool Size
22000
Surface
Vinyl
Chlorine
Liquid Chlorine
I’ve used the poolmaster to double check my Taylor kit early on in my testing experience, but ultimately you’re going to find the chlorine test is really limited, especially for how the TFP process works. Get the TF-100 instead as soon as you can and let the poolmaster go.

I just yesterday emptied out the poolmaster reagent containers and repurposed the poolmaster container (all a couple of years old at this point!) to hold extra reagents, a testing vial, and my sample sizer. It’s not perfect but better than wasting the plastic 😁
 
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Sneauxball

Member
May 1, 2021
8
Montgomery, TX
Pool Size
13280
Surface
Plaster
The Poolmaster is not what we would refer to as one of our recommended kits, but it's better than test strips, so use it for now. About TA, you have to use the acid, but the acid has a most dramatic effect on pH first, and the TA falls in slower increments. That's why we pull the pH down to about 7.2 with acid, then the TA may fall 5-10 ppm at a time. When the pH rises high, use acid again and repeat the process until you are happy wit the TA (probably 60-80 range) to help keep the pH more stable.

Tabs (pucks) contain stabilizer (CYA), and after just a few tabs you find your CYA level reaching a maximum point. That's why they are only safe to use for a short period, after that, it's regular bleach or liquid chlorine (same thing). Those do not have stabilizer in them. Pool builders and pool stores are happy to sell you tabs at $120 a bucket, but don't tell you than in 6 months you'll have to drain your pool because those same tabs increased the CYA too high. Before I got my salt generator, I added chlorine each day for 7 years. Not a big deal, I just took my time and poured slowly. You'll be a pro at this before you know it.
Texas Splash, thanks, I’ll test tomorrow with the new kit and look at all of this again.
 

wireform

Silver Supporter
In The Industry
Aug 15, 2017
2,292
Spring Valley, NY
Craig,
We mean your best interest here so take the advice and run with it. We have nothing to gain nor anything to sell except free pool care at it's BEST. This forum has really grown as members came with pool problems and after hanging in turned the pool around to crystal clear with perfect chemistry. So, step one is get the recommended TF-100 kit along with the highly recommended speed stirr from tftestkits.net, Step two is to fill in your signature so we have an understanding what pool and equipment you have.
 
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Sneauxball

Member
May 1, 2021
8
Montgomery, TX
Pool Size
13280
Surface
Plaster
Oh, the poolmaster also doesn’t have a CYA test which is THE key to maintaining proper chlorine levels!
Thanks CraigChing, I’ll order the Taylor kit. The muriatic acid gets the pH and TA down but creeps up too quickly. I’m new at this so maybe this is normal. My CYA has been in range but I’m using strips so who knows. Thanks for you advice.
 

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Sneauxball

Member
May 1, 2021
8
Montgomery, TX
Pool Size
13280
Surface
Plaster
Craig,
We mean your best interest here so take the advice and run with it. We have nothing to gain nor anything to sell except free pool care at it's BEST. This forum has really grown as members came with pool problems and after hanging in turned the pool around to crystal clear with perfect chemistry. So, step one is get the recommended TF-100 kit along with the highly recommended speed stirr from tftestkits.net, Step two is to fill in your signature so we have an understanding what pool and equipment you have.
Wireform, I’ll look at the speed stirr kit and order the TF-100. Thanks for your help.
 

CraigChing

Gold Supporter
Jun 15, 2019
137
Plymouth, Minnesota
Pool Size
22000
Surface
Vinyl
Chlorine
Liquid Chlorine
The muriatic acid gets the pH and TA down but creeps up too quickly. I’m new at this so maybe this is normal.
It depends on how fast and to what level. Listen to @Texas Splash , he’s the expert. Don’t lower pH until it hits 8.0 and you might find that your pool likes 7.8 which is perfectly ok!


My CYA has been in range but I’m using strips so who knows.
Definitely get a good kit with a CYA test like TF-100 or Taylor K2006c. The “c” is important if ordering the Taylor kit. Or keep it easy and get a TF-100 which is designed for maintaining a pool using TFP methods.
 
Last edited:

CraigChing

Gold Supporter
Jun 15, 2019
137
Plymouth, Minnesota
Pool Size
22000
Surface
Vinyl
Chlorine
Liquid Chlorine
Wireform, I’ll look at the speed stirr kit and order the TF-100. Thanks for your help.
I can’t second getting the speed stir enough! I just got the sample sizer as well which is a luxury, but not having to crouch down to see the meniscus is pretty nice! And I feel like it takes the subjectivity out of getting the sample size just right. Being a stickler for precision, I’ve tested it out and am satisfied that it provides better, more regular sizes than me eye balling it. Definitely not as important as the speed stir, but a nice addition later when you understand the need for consistency!
 
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Sneauxball

Member
May 1, 2021
8
Montgomery, TX
Pool Size
13280
Surface
Plaster
I can’t second getting the speed stir enough! I just got the sample sizer as well which is a luxury, but not having to crouch down to see the meniscus is pretty nice! And I feel like it takes the subjectivity out of getting the sample size just right. Being a stickler for precision, I’ve tested it out and am satisfied that it provides better, more regular sizes than me eye balling it. Definitely not as important as the speed stir, but a nice addition later when you understand the need for consistency!
Thanks CraigChing, I’ll get the Speed Stir too.
 
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