Lowering and balancing TA and pH

Elwood5487

Well-known member
May 3, 2020
48
SW Michigan
Pool Size
17000
Surface
Vinyl
Chlorine
Liquid Chlorine
Hi everyone,

Hope your pool season is starting out well (for those who have a winter season).

This is our second Spring as pool owners. Last year we inherited our pool with our home and had to shock the water half to death to get rid of the swamp. This season we opened the pool to crystal clear water but I'm struggling to get balanced.

Last year we used pucks and late in the season learned that our CYA was way too high, so this year I'm trying to manage the chemicals separately and using plain chlorine at 12.5%. So this is another learning curve for me.

Anyway, I'm confident I'll have chlorine in the proper range by tomorrow, but my pH and TA continue to rise. I have added nothing but chlorine to the pool so far this Spring except to lower the pH. I lowered pH a week or 10 days ago, but then the TA spiked (and continues to rise). After reading other posts about balancing chemicals, particularly TA and how the sweet spot is different per pool I feel less sure about what my next steps should be.

We are having friends over next weekend, so I am working daily to get the pool swimmable by then. Wed/Thurs I plant to do the overnight chlorine test to make sure the water is safe. My two questions are;
1. Is the over night chlorine test the best way to ensure the water is safe to swim?
2. For the pH and TA, is my next step to slowly lower TA and continue to test the two until they get into recommended range?

I believe my logs are viewable if you want to see these details.

Thank you!
 

mknauss

Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
44,321
Laughlin, NV
Pool Size
6000
Surface
Fiberglass
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-40
1. Is the over night chlorine test the best way to ensure the water is safe to swim?
That test is to see if there is organic material in the water consuming chlorine. It is not fool proof.
You can safely swim in a pool as long as the FC is above the minimum and at or below SLAM level based on your CYA. You must also be able to see the bottom of the pool in the deep end of the pool.
2. For the pH and TA, is my next step to slowly lower TA and continue to test the two until they get into recommended range?
When pH reaches 8, lower it to 7.4. The TA will be consumed every time you add acid.

You mentioned the TA is rising. TA only rises if either high TA fill water or baking soda/soda ash are added to the pool.
 

zea3

Mod Squad
TFP Expert
LifeTime Supporter
Jul 10, 2009
14,043
Houston, Texas
Usually you don't worry about TA. pH is the important value to watch. TA only comes into play when you are lowering pH. Your current TA is not bad, however the pH is still way to high. You will need to keep lowering it with muriatic acid until you get the pH around 7.2-7.5 Make sure your returns are pointed down, and do not use any fountains that churn the surface of the water while you are lowering pH. Once you get the pH down I would start SLAM Process, since the way your chlorine is being consumed you may have a little something trying to get started. A day or two of slam will probably take care of that.
 
  • Like
Reactions: RichardL

Elwood5487

Well-known member
May 3, 2020
48
SW Michigan
Pool Size
17000
Surface
Vinyl
Chlorine
Liquid Chlorine
That test is to see if there is organic material in the water consuming chlorine. It is not fool proof.
You can safely swim in a pool as long as the FC is above the minimum and at or below SLAM level based on your CYA. You must also be able to see the bottom of the pool in the deep end of the pool.

When pH reaches 8, lower it to 7.4. The TA will be consumed every time you add acid.

You mentioned the TA is rising. TA only rises if either high TA fill water or baking soda/soda ash are added to the pool.
Can you explain "at or below SLAM level based on your CYA?" I'm not sure I understand that.
 

Elwood5487

Well-known member
May 3, 2020
48
SW Michigan
Pool Size
17000
Surface
Vinyl
Chlorine
Liquid Chlorine
Usually you don't worry about TA. pH is the important value to watch. TA only comes into play when you are lowering pH. Your current TA is not bad, however the pH is still way to high. You will need to keep lowering it with muriatic acid until you get the pH around 7.2-7.5 Make sure your returns are pointed down, and do not use any fountains that churn the surface of the water while you are lowering pH. Once you get the pH down I would start SLAM Process, since the way your chlorine is being consumed you may have a little something trying to get started. A day or two of slam will probably take care of that.
Thank you.
 

mknauss

Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
44,321
Laughlin, NV
Pool Size
6000
Surface
Fiberglass
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-40
Can you explain "at or below SLAM level based on your CYA?" I'm not sure I understand that.
Your Poolmath logs show your CYA at 40 ppm. See FC/CYA Chart for SLAM level. It will be 16 ppm FC.
 
Thread Status
Hello , This is an inactive thread. Any new postings here are unlikely to be seen or responded to by other members. You will get much more visibility by Starting A New Thread