3 months after plaster going through 13 oz of acid a day, normal?

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QingGuy

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Mar 22, 2015
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Las Vegas NV
This very well may be normal but thought I'd check-in. I'm adding about 13 oz of acid a day to keep me around pH 7.6, is this normal? Water went in 6/14/15.

FC 5.5
CC 0 - .5
pH 7.9
TA 100
CH 290
CYA 70

Thanks in advance!
 
Not much you can do with new plaster other than babysit it often. This is from the plaster start-up page:
No matter what start-up procedure is used, your pool will consume a lot of acid during the first 6-12 months as the plaster finish continues to cure. It is important to test your pH daily and do not let it climb above 7.8. Be sure to continue to brush the pool at least weekly during this period.
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Pool School - Start-up New Plaster

- - - Updated - - -

Remember, aeration will add to pH as well, so if you have a water feature, spa, or SWG, they tend to rise pH as well.
 
Definitely lower your TA. That will help. I would suggest going to the bottom of your range or even lower. However you need to keep an eye on CSI and, if you do go lower than the recommended range, you'll need to add calcium to compensate for lower TA if the CSI is too negative.


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bdavis466 said:
A lower TA and borates would help with slowing the pH rise. Things should slow down somewhat as the plaster fully cures.

I add about double that per day for what it's worth.

The fill water plays a huge part as well.
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Dang, I just noticed I forgot to update pool math target on TA when I turned on my SWG. Did CYA but not TA. Yea I'll have to bring that down to about 60.

How long ago did you plaster and how many gallons is your pool if you don't mind me asking.
 
Plaster was in March of this year and the pool is 33,000 gallons. I have an acid pump (which I am very pleased with) that I run at the maximum setting (about 22-24 oz per day) and even that can not keep up. I have to manually lower the pH with about 48 oz. of acid every 2 weeks.

I keep the TA at 60, limit the aeration, and have 50 ppm of borates. Evaporation and fill water with 125 ppm TA is what I have to fight...that's just the way it is.

I noticed a decent decline in pH rise after about 6 months from the time the plaster was applied. I would think that what I am experiencing now will be the norm from here on out.
 
bdavis466 said:
A lower TA and borates would help with slowing the pH rise. Things should slow down somewhat as the plaster fully cures.

I add about double that per day for what it's worth.

The fill water plays a huge part as well.
Click to expand...

What he said! I added 50 ppm Borates and allowed my TA to drift down to 50 ppm and haven't seen any change in pH in months.... I was dumping in probably 2 gallons of MA every 3 weeks...

However, with plaster (and new plaster, at that), you're going to be married to the MA bottle for some time to come..... whatever, watch that CSI like a hawk....
 
Got some help from someone and realized I also didn't adjust my CH when I did pool math. Going to get my TA right, then pH and then CH. Adjusted pool math, DOH!

Truth be told, I was so focused on not over shooting my CYA that I totally missed updating TA and CH, in-spite of reading Pool School several times. What's the saying, can't see the forest for the trees?
 

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Be careful tossing around how much acid you add and comparing. There are different concentrations of acid out there that folks might be using. For example, I used 14.5% for a while before I got wise and found a source (the pool store of all places) that had the 31.45% stuff. Now I use half as much. :)

My fill up of the new pebble sheen finish was exactly a month after yours (7/15/2015) and I still dump in about a quart per week of 31.45% to get the pH from 7.8 - 8.0 back down to 7.2 - 7.4 ish.
 
My plaster is 5 months old, and it's still taking 1/3-1/2 gallon (~42 oz) of MA daily, with a TA of 60. Our waterfall also gets a ton of use, so that doesn't help the situation either.

The local Home depot has a good deal on 20 Baum MA, $10 or $12 for a pack of 2 gallons, its in the outside gardens section at mine. Even so it's still been about $60/month in acid this first season. I hope next year the acid demand isn't so high.
 
Going to be lowering my pH today and thought I'd post here rather than start a new thread. I'll be doing it according to pool school, however, can someone give me an idea on how long to aerate? I have one 48" sheer descent and two scupper pots. I was thinking of pouring in the acid and letting pump run for 30 minutes, then turning on water features for 1 hour then testing and repeating until I'm back at 7.6. Any suggestions?
 
There's really no way to know as aeration is not an exact quantity to measure. Even when you lower the pH of still water, the CO2 out gasses and the pH rises all on its own. Aeration just speeds up the process.

Best to test it to see but I doubt it will be hours. Probably more like a day or so. It's temperature dependent too as colder water is slower to outgas CO2 than warmer water.


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Agent99 said:
Be careful tossing around how much acid you add and comparing. There are different concentrations of acid out there that folks might be using. For example, I used 14.5% for a while before I got wise and found a source (the pool store of all places) that had the 31.45% stuff. Now I use half as much. :)

My fill up of the new pebble sheen finish was exactly a month after yours (7/15/2015) and I still dump in about a quart per week of 31.45% to get the pH from 7.8 - 8.0 back down to 7.2 - 7.4 ish.
Click to expand...
I use 29% from NPS

JoyfulNoise said:
There's really no way to know as aeration is not an exact quantity to measure. Even when you lower the pH of still water, the CO2 out gasses and the pH rises all on its own. Aeration just speeds up the process.

Best to test it to see but I doubt it will be hours. Probably more like a day or so. It's temperature dependent too as colder water is slower to outgas CO2 than warmer water.
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So are you saying I may need to run my water-features for a day or so? When would you test? Sounds like several hours after acid has been poured in for my first test to see a noticeable rise.

Another question, should I not run my pump that runs my filter and SWG, only run the pump that runs my water features? Reason I ask is I've heard very low pH can hard equipment, specifically my SWG.
 
As long as you don't go below a pH of 7.0, your equipment will be fine.

You don't have to constantly aerate unless you really want to drive the pH up fast. The other day I lowered my pH to 7 to drop the TA by 10ppm. Aside from adding the acid at the start of my long afternoon pump schedule, I really did not modify my aeration much from what I normally do. My pH stayed low (~7 to 7.4) for a day or so and is now hanging back at 7.6. If I wanted to get the pH to rise more quickly, then I could run my waterfall pump longer but that's a waste of electricity. I was in no hurry.


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QingGuy said:
Thanks, just poured in the acid, will test in 30 minutes and go from there. From the sounds of it if once I'm at 7.2 I just let my pH rise naturally I should be OK.
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Yup. In fact, you can do one better and go for a nice long swim with lots of splashing and cannonballs. Best way to naturally aerate the water is to go and have some fun in it ;)


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TA is now down to 70. I'm thinking one more good dose of Acid and I should be good. Would like to get down to 60. I should let the pH drift back-up to 7.8 and then take down to 7 again, correct?.

Then I'll tackle my CH. Going into "winter" I assume I'm still wanting to maintain these levels since I won't be closing the pool.
 
QingGuy said:
TA is now down to 70. I'm thinking one more good dose of Acid and I should be good. Would like to get down to 60. I should let the pH drift back-up to 7.8 and then take down to 7 again, correct?.

Then I'll tackle my CH. Going into "winter" I assume I'm still wanting to maintain these levels since I won't be closing the pool.
Click to expand...

PoolMath can tell you how much TA you'll consume for a given acid dose. Going back up to 7.8 lets you add a larger dose of acid and thus drop the TA further.

In the winter, you need to maintain your testing. You'll find that your chlorine consumption goes way down. For my pool last winter, I was able to run my pumps about 2-3 hours per day and the SWG output was about 20%. With that, I maintained 5.5-6ppm FC and 0ppm CCs consistently. Also, my acid doses were no more than 8oz once per week or so. Everything else just stayed where it was. The occasional rains had me do a few minor drains of water but nothing significant. CSI stayed down at -0.15 pretty much the entire winter.


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