Adding acid daily-help!

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palmspriings

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Feb 18, 2013
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Due to excessive calcium scaling and staining, I drained and acid washed my pool approx 3 weeks ago. I test my water daily with the TF 100 and do additions according to the Pool Calculator. My TA out of the tap was 180 and it took close to two weeks to get it to 80. Due to the hardness of water in PS, my goal is to keep my pH below 7.4 to ensure the staining doesn't repeat. However, my pH rises .3-.4 daily, here are the current numbers

CH 320
TA 80
FC 4
TC 4
CYA 32
pH yesterday after acid addition 7.3, today 7.6

Any advice would be appreciated, thanks for all of the help!
 
How long do you run your pump per day?
Are the returns aimed to where they're breaking the surface?

I'm asking these questions to see if there's something going on with the mechanics.

I'd let the TA come on down to about 70 and see if that helps.
 
The returns are underwater and the pump runs approx 4 hours a day. There shouldn't be any excess aeration going on.
I did consider taking the TA down to 70, but thought I'd explore other options before this one. I guess I don't have a lot of faith in this approach but will do if other options aren't obvious, thanks
 
Are you saying you don't have faith in lowering the TA? I'm not sure what you mean. I would take the TA down to 60. It's inexpensive and fairly easy to do if you can introduce some aeration.
 
Why do you want the pH to be 7.4? If its to avoid scaling, you just need to be sure your CSI is zero or very slightly negative. Based on your other tests, a pH anywhere below 7.6 should do that. Yes, you can lower the TA and it will help with pH rise, but you will always find that pH finds a "natural balance". As long as that yields an acceptable CSI, I don't fight it. Occasional additions of acid are all that's necessary to maintain that "natural balance". Fighting it without lowering the TA is a losing battle.
 
Dave, I don't have aeration, but I have slowly lowered in anyway. I thought 80 would be perfect as it is the low end of the scale. However I have been reading that if CH is high enough, then lowering it more is safe?

chiefwej, is it possible that the pH will find the "natural" balance if I let it go to 7.8? It is currently 7.6, maybe I will skip the addition and see what it does overnight. If it continues to climb, I will lower the TA as advised

Thanks!
 
There really isn't anything to worry about with your numbers where they are now. The PH could go up to 8 and you are still exceedingly unlikely to have any issues with calcium scaling. CSI up to +0.30 is considered just fine and a little higher than that is also fine as long as there isn't any chance of the PH going up further.

The amount of PH drift you experience is a function both of the TA level and the current PH. Higher TA means more PH drift and lower PH means more PH drift. The lower you try to keep the PH, the more you are going to have a problem with it. You can almost certainly get rid of the PH drift if you let the PH go up to 7.8 and keep TA between 60 and 80.

When you eventually add some more fill water, it will raise the TA again, and then you will need to keep the PH a bit lower until the TA comes down again. Once you get TA down to 80 again you can go back to allowing PH up to 7.8.
 
Jason
The pH did jump to 8, again, up .4 daily. An oddity is that the TA went down to 70, yet I didn't add any acid yesterday. I tested both twice in case of error. Todays numbers

CH 320
TA 70
FC 2.5
TC 2.5
CYA 38
pH 80

Lots of changes from yesterday. When plugging these numbers into the pool calculator, I go into the danger zone if I try to bring the TA to 60 and pH to 7.1 to allow the TA to come down...CSI=-.75. It looks as if the only safe way to adjust is to leave the TA at 70 and lower the pH to 7.5, giviing me a CSI of -.29. If I don't find out what is going wrong, I'm going to end of in the same mess that I just cleaned up, as the CH jumped 40 overnight (2 days ago) and for some reason, the TA is dropping as is the chlorine 1.5 (non combined) I don't have any pucks in the water, just using bleach and acid. Any ideas?
Thanks again!
 

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At best the tests are +-10. So TA of 70 and TA of 80 are essentially the same result.

The safe range for CSI is from -0.6 to +0.6. And numbers near that range aren't going to cause short term problems. If CSI goes below -1 or above 1 you have something to worry about.

Using your current readings and a water temperature of 80 degrees I get a CSI of 0.38, which is not in any sense in the "danger zone". If your water temperature is lower then the CSI will be lower but still 0 or above, which is also fine.

Bringing the PH down to 7.1 for a few hours, or even a few days, is not be a problem, though there really isn't any need to do that. You are trying to make very small changes to TA, so there is no need to make huge changes to PH.

With CH in the 300s and TA below 100 there really isn't anything to worry about. You need to pay a lot more attention when/if CH and/or TA go up significantly higher, but where you are now really isn't risking any kind of problem as long as you keep PH even roughly in the normal range.
 
I understand what you are saying. The prompt for this thread is that I can't keep the pH down. Yes, the current numbers are ok, but only if I add acid every day. If I go away for a three day weekend, I'm screwed, lol! After reading the initial responses, I bypassed the acid yesterday, hoping it would find it’s “natural” balance. But instead it rose its usual .4 from 7.6 to 8!

The other plan of action was to lower the TA, but if 80 is 70 and 70 is 60, I guess I’m already there ? Living in the desert, I need to get the pH under control now before temp are in the high 100's and water temps in the low 90’s…… for three relentless months-hot! We've recently had temps in the high 90's to low 100's and this evaporation has raised the CH and CYA. So yes, where I am now is ok, but the pH does not stay in the normal range without daily acid additions. As the heat turns up and the CH and TA climb, I expect this battle to continue.

I hear you saying all is good ? but I’m not understanding why. Am I missing something?
Thanks for your time, I greatly appreciate the feedback!
 
Your TA is currently 70-80. You can lower it to 60 safely. Lowering TA will lower the rate of PH increase. You can still lower TA a little more (down to 60 on the test) without problems. If you really need to you can add borates, and then you can lower TA even further (down to 40).

The PH does not increase without bound. It will stabilize at around 8.4. You still want to maintain PH below 8, but if something goes wrong the PH won't go above 8.4. You are safe right now because even with PH at 8.4 your CSI is still only marginal, not horrible. As long as it doesn't sit at 8.4 for too long there won't be issues.
 
I have been managing my pool with very high CH levels for a couple years now, with no scaling. I just reduced the TA and then added borates. That makes it much easier to maintain a reasonable CSI even with CH levels near 1,000. I'm planning on draining and refilling this spring, but my fill water starts out about 375 CH. With desert heat and evaporation rates here in Tucson, CH will be back sky-high again in no time.
 
OK, so I have had my TA stabilized at 50-60 for over a week, but the pH is still increasing .3 every day.
Here are the numbers for the last 4 days. With the exception of pH, assume other readings remain the same....I have added chlorine to maintain 3ppm, but have held off on acid additions to see what it would do. Is there anyway that this daily increase in pH is "normal" in warm, sunny climates? I don't know what else to do.

CH 400
TA 60 60 60 60
pH 7.1 7.5 7.8 8.1
TC 3
CC 0
FC 3
CYA 30


As always, I appreciate the help!
 
palmspriings said:
OK, so I have had my TA stabilized at 50-60 for over a week, but the pH is still increasing .3 every day.
Here are the numbers for the last 4 days. With the exception of pH, assume other readings remain the same....I have added chlorine to maintain 3ppm, but have held off on acid additions to see what it would do. Is there anyway that this daily increase in pH is "normal" in warm, sunny climates? I don't know what else to do.

CH 400
TA 60 60 60 60
pH 7.1 7.5 7.8 8.1
TC 3
CC 0
FC 3
CYA 30


As always, I appreciate the help!
Click to expand...
I add acid 2-3 times a week with my TA bouncing between 50 & 60. CH is over 800. I believe the TA increase and the pH rise is because I am slowly stripping scale off the walls. Maybe that's what's happening with you, too.
 
palmspriings said:
Richard
Thanks for the response. I just had all of the scaling removed, so I was hoping for more stablization with this pH. Afraid to leave town, you know :)
Click to expand...
You have room for more CYA. And trichlor is acidic. I suggest you get a floater and a small bucket of pucks. It will raise CYA, maintain FC, and maintain pH for you while you're gone.
 
Richard320 said:
palmspriings said:
Richard
Thanks for the response. I just had all of the scaling removed, so I was hoping for more stablization with this pH. Afraid to leave town, you know :)
Click to expand...
You have room for more CYA. And trichlor is acidic. I suggest you get a floater and a small bucket of pucks. It will raise CYA, maintain FC, and maintain pH for you while you're gone.
Click to expand...
Already have these ready to go.....it's my summer plan Richard! I'm keeping my CYA on the low side for now, so I can use the pucks in the summer. Chasing both pH and chlorine is not on my agenda :p
 

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