I could use some advice/affirmation.

curleah

Active member
Feb 23, 2011
26
Northeast OK
#1
The pool is full. The water turned green on me this year, the filter is running and we are preparing to shock. I've been doing the BBB method for several years but always seem to question myself at start up time. Here are my current test results:
FC-0
TA-50
CH-120
PH-way high...off the color chart
CYA-40

I know I need to lower my PH before I begin the shock process but am a little concerned about how low my TA is. According to the pool calculator to lower my PH from 8.2-7.2 I need to add 42 oz. of muriatic acid. I will retest after adding acid before I begin shocking. Is there anything I am forgetting?
 

kimkats

Mod Squad
LifeTime Supporter
Jul 10, 2012
36,812
Tallahassee, FL
#2
Since you are going to have to push the PH so far down I would get the TA up to about 70 to give you some wiggle room for it to drop while you drop the PH. TA is raised by adding baking soda. Easy and cheap to use so reason to not do it. The main reason I say this for you is the fact you have a vinyl liner and I ruined my liner on my last pool by having the pH and TA all messed up so I tend to error on the safe side.

Kim:kim:
 

Richard320

TFP Expert
LifeTime Supporter
Jan 6, 2010
20,330
San Dimas, CA (LA County)
#3
I tend to think the opposite. I'd leave TA where it is, simply because it's not that low, and it will likely climb as you replace water lost to backwashing. That filter's going to load up while you're clearing the swamp.
 
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curleah

Active member
Feb 23, 2011
26
Northeast OK
#6
Ok, my PH is still off the charts after adding 42 liquid oz muriatic acid. As I said, the water is green. I thought maybe my test kit was old so I had the pool store check my PH. They show it off the charts as well. They told me that if the water is green adding muriatic acid will not drop it. Is this correct? Do I start shocking where I am or add more acid? I thought my PH needs to be between 7.2-7.4 before shocking?
 

Richard320

TFP Expert
LifeTime Supporter
Jan 6, 2010
20,330
San Dimas, CA (LA County)
#7
The pool store is full of misinformation. You can adjust pH no matter what the water looks like.

Your pH could be something like 8.6, but it will only read as 8.2. So repeat the calculation and dose it again. Half an hour with the pump on, even less if you do some brushing, and retest and repeat. Eventually, you'll get a color shift below 8.2, and then you can make the final adjustment and then it's jugs away!

Remember, the pH scale is logarithmic. The drop from 9 to 8 is ten times larger than the drop from 8 to 7. So it'll take huge amounts of acid to shift it down below 8, and then the numbers should get reasonable.
 
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curleah

Active member
Feb 23, 2011
26
Northeast OK
#10
Ok, I've added muriatic acid 3 times. First 42 oz, then another 42 oz, then another 55 oz. The first addition was yesterday. The last two additions were in the last hour and a half. I waited 30 minutes or more after each. The PH is still testing higher than 8.2. So, I just keep going?
 

Richard320

TFP Expert
LifeTime Supporter
Jan 6, 2010
20,330
San Dimas, CA (LA County)
#11
Ok, I've added muriatic acid 3 times. First 42 oz, then another 42 oz, then another 55 oz. The first addition was yesterday. The last two additions were in the last hour and a half. I waited 30 minutes or more after each. The PH is still testing higher than 8.2. So, I just keep going?
My gut says yes, but I should ask, have you added any bleach? Because FC levels over 10 can react and give the pH test a purplish tint that looks much higher than 8.2.
 
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curleah

Active member
Feb 23, 2011
26
Northeast OK
#13
My gut says yes, but I should ask, have you added any bleach? Because FC levels over 10 can react and give the pH test a purplish tint that looks much higher than 8.2.
I still haven't added bleach and I have now added 2 gallons (252 oz.) of liquid muriatic acid. It's still reading off the color chart. This seems completely ridiculous to me. I am not sure how to proceed forward. Can I do damage by continuously adding acid to my pool? It's green and I want to SLAM but my PH is not in the 7.2-7.4 range. This has never happened before. I have used the same PH test kit for several years, perhaps it's expired? The pool store showed it off the charts before my last gallon addition as well. Please help. Do I continue to add acid?
 

Richard320

TFP Expert
LifeTime Supporter
Jan 6, 2010
20,330
San Dimas, CA (LA County)
#14
I still haven't added bleach and I have now added 2 gallons (252 oz.) of liquid muriatic acid. It's still reading off the color chart. This seems completely ridiculous to me. I am not sure how to proceed forward. Can I do damage by continuously adding acid to my pool? It's green and I want to SLAM but my PH is not in the 7.2-7.4 range. This has never happened before. I have used the same PH test kit for several years, perhaps it's expired? The pool store showed it off the charts before my last gallon addition as well. Please help. Do I continue to add acid?
Sounds like.

Question: did you, by chance, end up with the "safe" or "low-fuming" acid? That's like half-strength but full price, and will not get you the results you should be getting if you've been using 31.45% in poolmath.
 

kimkats

Mod Squad
LifeTime Supporter
Jul 10, 2012
36,812
Tallahassee, FL
#15
You know what I want you to do....................get one gallon of your pool water in something you can stir good. Add 1/2 oz of muriatic acid to it and stir it up good. Then test for PH. Just to scratch this itch. This should PLUNGE the ph down in your gal of water.
 
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curleah

Active member
Feb 23, 2011
26
Northeast OK
#16
Sounds like.

Question: did you, by chance, end up with the "safe" or "low-fuming" acid? That's like half-strength but full price, and will not get you the results you should be getting if you've been using 31.45% in poolmath.
I did notice that the bottle said 90% less odor. I considered that maybe it wasn't as strong but I couldn't find the strength on it when I checked yesterday. Funny you mention this cause I sent my husband to a different store to buy a different brand just before receiving this.

- - - Updated - - -

You know what I want you to do....................get one gallon of your pool water in something you can stir good. Add 1/2 oz of muriatic acid to it and stir it up good. Then test for PH. Just to scratch this itch. This should PLUNGE the ph down in your gal of water.
Great idea!
 

Richard320

TFP Expert
LifeTime Supporter
Jan 6, 2010
20,330
San Dimas, CA (LA County)
#17
I did notice that the bottle said 90% less odor. I considered that maybe it wasn't as strong but I couldn't find the strength on it when I checked yesterday. Funny you mention this cause I sent my husband to a different store to buy a different brand just before receiving this.

- - - Updated - - -
Rule of thumb for bleach and acid: If they're ashamed to post the strength, you don't want it.
 

kimkats

Mod Squad
LifeTime Supporter
Jul 10, 2012
36,812
Tallahassee, FL
#20
YEA FOR ORANGE!!!

Okay so act as if your acid is 14% and use that in Pool Math. Keep hitting it until you see orange on your test for the whole pool water. It will be a battle but one you know you can win. Next time you buy acid look outside for the 31%. My Lowes has them in 2 jug boxes.

Kim:kim: