How can I lower my TA to 80 without also dropping the pH down into the acid range?

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three4rd

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Jul 20, 2014
206
Berks County, PA
Hi,

I just got my pool replastered and a fresh fill added. The start-up guide I got from my plasterer calls for the TA to be at 80 and the pH between 7.2-7.6. I use dry acid (sodium bicarbonate) - a BioGuard product called "Lo 'N Slo". What I've found is that, while it brought down the pH to 7.4 from the original 8.8 of the fresh fill, the TA has only dropped from 170 to 150. I can't imagine how I would have gotten the TA down to 80 on the first day after filling. Actually, I can't imagine even getting the TA that low unless I would also bring the pH way down - probably into the acid range. I guess I could take the pH a bit lower, but I'll bet that will only drop TA down to 120-130. Any suggestions? If there is no problem with the new plaster with the TA at 150 where it is now, I won't even worry about it. My TA has hardly even been that below 100 except for one time when it was 66. The pool store told me to bring it up.

Thanks for any thoughts. I don't want the new plaster to scale, but neither do I have any idea how to bring down this current TA reading without also dropping the pH lower.
 
three4rd said:
Hi,

I just got my pool replastered and a fresh fill added. The start-up guide I got from my plasterer calls for the TA to be at 80 and the pH between 7.2-7.6. I use dry acid (sodium bicarbonate) - a BioGuard product called "Lo 'N Slo". What I've found is that, while it brought down the pH to 7.4 from the original 8.8 of the fresh fill, the TA has only dropped from 170 to 150. I can't imagine how I would have gotten the TA down to 80 on the first day after filling. Actually, I can't imagine even getting the TA that low unless I would also bring the pH way down - probably into the acid range. I guess I could take the pH a bit lower, but I'll bet that will only drop TA down to 120-130. Any suggestions? If there is no problem with the new plaster with the TA at 150 where it is now, I won't even worry about it. My TA has hardly even been that below 100 except for one time when it was 66. The pool store told me to bring it up.

Thanks for any thoughts. I don't want the new plaster to scale, but neither do I have any idea how to bring down this current TA reading without also dropping the pH lower.
Click to expand...


Welcome to TFP :wave:

LO 'N Slo is sodium BISULFITE (a dry acid) not bicarbonate. Sodium bicarbonate would raise your pH while sodium bisulfite lowers the pH.

Since you have a new plaster surface, your TA will be very high. The only way to lower TA is to use the acid-aeration process describe here -

http://www.troublefreepool.com/content/129-how-to-lower-lowering-total-alkalinity

or to fill a pool with water that has a low TA to begin with.

There is also an article for how to start up a newly re-plastered pool here -

http://www.troublefreepool.com/content/154-start-up-new-pool-plaster
 
The PH will continue going up rapidly for roughly a month after fresh plaster is applied. The continued acid additions to keep the PH in line will slowly get the TA into line.

Focus on the PH for the first few weeks, which is by far the most important thing.
 
Thanks for the advice. I actually meant sodium bisulphate - wrote the wrong thing. I added a bit more dry acid tonight which will probably take the pH down to 7.2. I'm not going to drop it any lower than that. Hopefully, as was suggested, gradually the TA will continue to lower. With the hardness level about where it should be, I don't believe I need to worry about the new plaster scaling.
 
I want to check on whether this is sound advice that I just received from my pool store regarding my initial inquiry about wanting to lower the TA but not the pH. They suggested that I just keep adding dry acid until the TA level that I want is achieved - even if the pH drops into the acid zone, and then add sodium carbonate (soda ash) to bring the pH back up. I then asked her if the soda ash won't also bring the TA back up also and she said not. So now I have two questions - 1) is the info she gave me accurate? 2) is it SAFE for the new plaster to take the pH down that low - I'm really hesitant to go that heavy on the sodium bisulphate. It does work well to bring down the pH but has brought down the TA rather slowly. My whole problem is that I want to continue to lower my TA but keep the pH where it is if at all possible. I know about the aeration procedure, but really don't have the means to accomplish that. Thanks for any advice.
 
I wouldn't do that... I would focus on the pH first. You can/will bring the TA down with the acid additions. If you have no way of aeration, you can build a little water jet or just throw a pool party and hold a cannonball competition. :p
Also, visit http://poolhelp.com/onbalance.aspx


Alkalinity:
http://poolhelp.com/handouts/oB_A Deeper Look at Alkalinity Handout.pdf

What they are proposing you do is an "acid start up" - more or less. Many people have done this...and very few have problems. For me the risk wasn't worth the "gains". So I went against my PB's recommendations, and performed a startup as described on poolhelp.
http://poolhelp.com/handouts/oB_Acid Startups for Plaster Pools Handout.pdf
 
How can I lower my TA to 80 without also dropping the pH down into the acid r...

three4rd said:
I want to check on whether this is sound advice that I just received from my pool store regarding my initial inquiry about wanting to lower the TA but not the pH. They suggested that I just keep adding dry acid until the TA level that I want is achieved - even if the pH drops into the acid zone, and then add sodium carbonate (soda ash) to bring the pH back up. I then asked her if the soda ash won't also bring the TA back up also and she said not. So now I have two questions - 1) is the info she gave me accurate? 2) is it SAFE for the new plaster to take the pH down that low - I'm really hesitant to go that heavy on the sodium bisulphate. It does work well to bring down the pH but has brought down the TA rather slowly. My whole problem is that I want to continue to lower my TA but keep the pH where it is if at all possible. I know about the aeration procedure, but really don't have the means to accomplish that. Thanks for any advice.
Click to expand...

Once again, ridiculous pool store advice....

Step 1 - Assume everyone in the pool store is outright lying to your face

Step 2 - Always consult TFP Pool School for correct info

So, the easiest way to drop your pH and TA at the same time is to use good old muriatic acid. Then, to keep TA low, the way to naturally raise your pH without affecting TA is to aerate the water either by running waterfalls or spa spillways or pointing return jets up to break the waters surface. Many users of these forums have also constructed various water spaying devices using PVC pipe that screws into a return. You can look up "Water Coolers" to find some ideas. You can also aerate simply by vigorously brushing your pool walls or letting the neighborhood kids splash around in the water.

Adding any kind of carbonate salt to the water raises both the pH and TA and thus defeats the point of adding the acid in the first place.

Also, dry acids, while easier to use than MA, cost more money and don't drop your TA nearly as fast as MA. Obviously MA has to be added more carefully and slowly than dry acid, but it works a lot better (in my opinion).

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Plaster is 5 days old, which is why I'm so concerned about all this. Given that the pH levels will probably continue to rise, I don't think this is something that will resolve itself today or tomorrow. Ping - I like this advice about focusing on the pH. Sunny Optimism - LOL about the "ridiculous pool store advice". I'm just a bit hesitant to use MA, preferring the dry acid since it is safer to work with. Mrcarcrazy - also LOL about the cannonball competition! I wish my return jets were adjustable - they aren't the two return lines simply end at the pool wall and direct the water straight in on an angle. Thanks for the handout links. I read about acid start up and wasn't real thrilled. As my pool plasterer just told me, you can remove deposits but you can't put back on what has been etched. I think I'll just stay the course here with keeping the pH in check, or at least not below 7.2, and see where the TA goes. With constantly brushing the pool right now, I don't see how I will achieve a low-range TA within the next few days.

I really appreciate all the helpful advice. I know that I need to get a better grasp of the whole water chemistry picture and how everything interrelates. My pool plasterer is also a bit concerned about my saturation index, which the pool store tested as being 1.5 and that, over the long run, this really should be lowered.

Many thanks again. I certainly welcome additional thoughts!
 
Pool Math http://www.troublefreepool.com/calc.html is your friend. That will tell you your saturation index. That is it will tell you your saturation index IF you are using reliable home testing with a drop based kit. Pool store results for any numbers put into Pool Math should be considered rough estimates at best, outright lies at worst.

If you're not testing yourself at home, save the gas money you'd spend (waste) going to the pool store and get a great kit like the TF-100 or K-2006.
 

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Definitely focus on pH. Test a lot and keep it as low as you possibly can.

As for MA safety, I guess I'm just used to it because I worked in chemistry labs around that and every other concentrated acid and dangerous chemicals my whole working life. Lots of HazMat training for me. MA is by far the easiest of the concentrated liquid acids to work with and the least likely to cause skin burns on direct contact (has to sit on your skin for a while). Sulfuric acid and nitric acids are much nastier and will peel the skin off of you...let's be glad pools don't use that stuff :)

If dry acid works for you, that's fine. It's just not as fast acting as MA and costs more.


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Thanks JVTrain,

More great advice! I just talked to my plasterer and he advised that I learn how to work with a saturation index calculator. I assume that the link you gave me is essentially what he is referring to. I have the K-2006 as per my plasterer's recommendation. I find it to be a great kit and the TA numbers were very close to what my pool store came up with. The only thing about the Taylor's pH testing is that there is no way to measure above 8, but then again what does it matter? Above 8 is above 8 and needs to be lowered anyway. I can see already that I'll need to get extra reagents on hand, especially the Calcium buffer and Sulfuric acid. I'm amazed at how some reviewers of this kit said how complicated they found it to be. I mean, the instructions for the basic tests are right on the lid and easy to follow. Also, everything is color-coded. I found it really easy to use.
 
SunnyOptimism,

Thanks. All the advice I'm getting here is to keep focusing on the pH, which has been my gut feeling as well. I'm not going with the pool store's advice to just go overboard with the sodium bisulphate until I turn the water chemistry acid - then bring the pH back up with sodium carbonate, hopefully leaving the TA at the low range that I'm looking for. That just sounds like a bad idea. As long as I am not doing the new plaster any harm with my current numbers (pH - 7.6, TA - 150, CH - 170), I'm not going to panic.
 
Just a quick update - TA is starting to drop with continued dry acid additions. I'm now at 140 TA with the pH at 7.4. I don't see any need to bring it down below 7.2. It'll creep up anyway with the new plaster for quite some time I would imagine. I'm hoping continued acid will keep working at bringing down the TA.
 
Thanks SunnyOptimism,

I'm trying....tonight the numbers are 7.2 pH and I'd say 135 TA - the color changes somewhere between the addition of the 13th and 14th drop the way it appears to me. The 14th drop of the reagent made the reddish color (changes from green to red) a bit darker than usual, so I'm going with a number in between 130 and 140. I guess I wouldn't be off by too much. Now - I'm hoping that the pH goes back up some by tomorrow morning so that I can add more acid and maybe bring the TA down a bit further. Otherwise I'm really hesitant to go much farther down on the pH. What do you think? I don't really feel comfortable taking the pH down to 7. Does that seem reasonable? Actually I think the TA where it is now is not all that bad. I can't see how I'd get it down to 80 as recommended in my start-up guide I got from the plasterer.

Thanks again for your input and encouragement!
 
Forgot to add....using Pool School's calculator, I come up with a CSI of -0.26. Now I'm more scared than ever! Isn't this in the etching zone - anything below -0.3? I just don't know what to do anymore. According to the calculator, if I bring the pH to 7 and assuming the TA would drop a few numbers down to 130, then the CSI should be at -0.48, which I guess is safer for the plaster. But then again isn't the lower pH in general more aggressive on the plaster? I think I need HELP :(
 
Plaster doesn't degrade that quickly at the levels you are talking about. The CSI and pH recommendations are for longer-term protection over months and years. Don't worry about what is happening during a TA lowering process. If there is concern, it would be pouring strong acid too quickly without circulation. This is why we suggest pouring concentrated chemicals slowly over a return flow with the pump running and then lightly brushing the side and bottom of the pool after the chemical additionl
 
Hi Chem geek,

I think I'm probably psyching myself out over all this. Actually, the one calculator I used indicates that a SI of -0.29 is actually pretty well balanced. When I filled the pool, my readings were pH - >8.8 TA - 174 CH - 199 SI - 1.5. So I've pretty much been adding acid ever since. Thanks so much for your reply. I always brush after my dry acid additions, just in case there are any undissolved pieces. From all the replies I got, it appears the most important thing I need to focus on right now is keeping the pH in check.
 
Your doing fine. I know how it feels to be the owner of that new pool and how easily you can get your shorts in a bunch. You need to open a can of POP (pool owner patience, not mine someone else's invention but very apropos) and RELAX!

You're doing fine. I'm totally cool with taking my pool down to 7. Once I had it down to 6.8 and it survived....so what if my raised wall has a crack in it, the kids fingers fit in there nicely to seal it up :p (joking!!!)

Keep up the acid aeration process and you'll be there in no time. If you get tired of brushing go find a neighborhood kid whose momma says "he's just big boned is all" and pay him a couple of bucks to do lots of cannon balls in the deep end ;)



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