I had my pool replastered 6 months ago. I bought a Taylor K-2005 test kit and test my water every 3 days. I am putting in an average of 16 oz of muriatic acid (14.50% Hydrogen Chloride) each day. The pool is 15,000 gallons. This is required to keep the level at 7.6. I buy my acid at Home Depot. The Total Alkalinity of the water is 80 ppm. This amount of acid seems excessive and is costly. I keep waiting for the amount of acid required to slow down, but there is no change. Any suggestions will be must appreciated!
Acid Demand
- Thread starter jamese
- Start date
- May 23, 2015
- 25,729
- Pool Size
- 16000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-60
The rate of pH rise is directly related to how much aqueous CO2 outgasses from the pool water. Due to bicarbonate equilibrium, your pH will always rise. Your TA, for the mist part, is a measure of carbonate alkalinity. The lower your TA, the less dissolved CO2 is in the water and the less driving force there is for outgassing. Low pH also drives more of the bicarbonate alkalinity towards aqueous CO2, so maintaining a higher pH results in lower outgassing rates.
If you provide more test data (include CH), then TFP can suggest a strategy for reducing acid demand. If you are following your PB or plaster applicators demands for warranty coverage, then there may no be anything you can do. Often times the warranty demands are silly and drive unnecessary acid demand. So you have to balance that against your time spent babysitting the pH.
By the way, 15% MA is likely costing you more money as it is routinely priced the same as 20 baume (31.4%) MA. You would use half as much acid per dose (8oz) if you switched and you’d likely save some money.
If you provide more test data (include CH), then TFP can suggest a strategy for reducing acid demand. If you are following your PB or plaster applicators demands for warranty coverage, then there may no be anything you can do. Often times the warranty demands are silly and drive unnecessary acid demand. So you have to balance that against your time spent babysitting the pH.
By the way, 15% MA is likely costing you more money as it is routinely priced the same as 20 baume (31.4%) MA. You would use half as much acid per dose (8oz) if you switched and you’d likely save some money.
- May 3, 2014
- 62,732
- Pool Size
- 6000
- Surface
- Fiberglass
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-40
Welcome to the forum!
Can we get some more information? Filling out your signature is great first step. Also if you have any water features that run a lot, etc.
I suggest you read ABC's of Pool Water Chemistry and consider reviewing the entire Pool School eBook.
Can we get some more information? Filling out your signature is great first step. Also if you have any water features that run a lot, etc.
I suggest you read ABC's of Pool Water Chemistry and consider reviewing the entire Pool School eBook.
Hi TFP
I just tested the water:
Free Chlorine - 2.0 ppm
Combined Chlorine - 0
PH - 7.7 ppm
TA - 60 ppm
CH - 390 ppm
CA - 40
I will add baking soda immediately to bring TA up to at least 80 ppm.
I previously used 3" chlorine tablets, however, the company that replastered the pool recommended using liquid chlorine. They said tablets have conditioner built in and that will raise the CA levels to an unacceptable high level.
What type of chlorine do you recommend?
Should I be concerned about the CH level? Last time I tested 2 1/2 months ago it was 300. Now it is 390.
Thanks in advance for your kind assistance and advice.
jamese
I just tested the water:
Free Chlorine - 2.0 ppm
Combined Chlorine - 0
PH - 7.7 ppm
TA - 60 ppm
CH - 390 ppm
CA - 40
I will add baking soda immediately to bring TA up to at least 80 ppm.
I previously used 3" chlorine tablets, however, the company that replastered the pool recommended using liquid chlorine. They said tablets have conditioner built in and that will raise the CA levels to an unacceptable high level.
What type of chlorine do you recommend?
Should I be concerned about the CH level? Last time I tested 2 1/2 months ago it was 300. Now it is 390.
Thanks in advance for your kind assistance and advice.
jamese
You can use regular (no splashless, no color, no scent, etc.) bleach which is usually 6%, or you can buy liquid chlorine at your local hardware store (Lowes, Home Depot, Ace), or often Walmart carries it. It is usually 10-12%.
Tablets will raise your CYA. It's best to keep those for vacation use. At 40ppm you're probably good right now unless you get a lot of hot sun, then perhaps you may need to raise that to 50ppm. I'd stick with 40 for now and see how much chlorine you lose to the sun every day.
Also, note that for your CYA level, your minimum should be no less than 3ppm. You need chlorine right away. Raise it to 7ppm at night, expect ~50% to burn off with the sun, which should leave you above your minimum every night. Then rinse and repeat. I like to do 1ppm over, to help account for unknown swimmers. Remember though, with swimmers you're going to need more chlorine. It's good to test before people swim and then afterwards. That will tell you more about how much you lose to bodies. Many people boost FC to target level before people swim to remain safe (above minimum).
Check out ABCs of Pool Water Chemistry and also PoolMath which will tell you how much chlorine to add to get to your target/minimum.
Tablets will raise your CYA. It's best to keep those for vacation use. At 40ppm you're probably good right now unless you get a lot of hot sun, then perhaps you may need to raise that to 50ppm. I'd stick with 40 for now and see how much chlorine you lose to the sun every day.
Also, note that for your CYA level, your minimum should be no less than 3ppm. You need chlorine right away. Raise it to 7ppm at night, expect ~50% to burn off with the sun, which should leave you above your minimum every night. Then rinse and repeat. I like to do 1ppm over, to help account for unknown swimmers. Remember though, with swimmers you're going to need more chlorine. It's good to test before people swim and then afterwards. That will tell you more about how much you lose to bodies. Many people boost FC to target level before people swim to remain safe (above minimum).
Check out ABCs of Pool Water Chemistry and also PoolMath which will tell you how much chlorine to add to get to your target/minimum.
Don't raise this TA, that will just make the pH go up faster. Let the pH go a little higher, say 7.8 to 8.0
Thanks all for your advice. A couple more questions. My kids are grown and the pool never has swimmers. No plants or trees are near the pool that can drop leaves, etc. Is it necessary to shock the pool occasionally? How often? What type of shock should I use? Shock with liquid chlorine or granulated? What type of granulated? Calcium Hypoclorite? Thanks again!
Why doesn't the pool have swimmers? That's the whole point of a pool, lol.
If you follow the TFP method, then there is no reason to "shock" a pool. TFP recommends keeping the FC per the FC/CYA Levels. If you keep FC above minimum levels, there is no need to regularly raise FC to a high level.
TFP recomends using liquid chlorine. This has not side effects that add chemicals that the pool doesn't need. Calcium Hypochlorite can be used unless you have hard water. You also need to monitor CH more often if you used the Cal-Hypo to make sure you don't create an issue that leads to scale buildup.