15 month old pool using 48 - 62 oz of acid a week

[QingGuy]

Acid consumption seems high now that plaster (quartzscape) is a year old. Thought I'd post here to confirm.

Yesterday's numbers:
FC 4
CC .5
pH 7.9 (prior to adding 32 oz of acid I shoot for 7.5)
TA 100
CH 400
CYA 70


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[Texas Splash]

First thing I would try is lowering that TA a bit by following the TFP Pool School - Lower Total Alkalinity page. Shoot for a new TA target of 70 or so and see how well that helps. If you have any products that generate aeration (waterfall, bubblers, etc) that can be adjusted lower that may help as well.

 

[QingGuy]

Thanks, I'll give it a shot.


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[QingGuy]

First thing I would try is lowering that TA a bit by following the TFP Pool School - Lower Total Alkalinity page. Shoot for a new TA target of 70 or so and see how well that helps. If you have any products that generate aeration (waterfall, bubblers, etc) that can be adjusted lower that may help as well.

Started this today. Any idea how long I should run my water features after I take pH down to 7? I understand it varies, just looking for ballpark. I have two water pots and one 48" sheer decent. I was thinking I'd run it for 1.5 hours and then check pH and TA.

 

[Texas Splash]

That's what I would do. Run the sheer and check a couple hours later. After doing that a couple times you should begin to see a pattern of how aeration increases your pH.

 

[QingGuy]

That's what I would do. Run the sheer and check a couple hours later. After doing that a couple times you should begin to see a pattern of how aeration increases your pH.

Took pH down to 7.2 (actually was probably 7.1) and it lowered TA to 70. Ran water features for 2 hr and it brought pH back-up to 7.4 so all looks good pH and TA wise, HOWEVER, now my CSI is -.45 "Potential to become corrosive to plaster" so now what?

According to Pool Math I need to take my pH back-up to 7.6 to to balanced. Suggestions? Do I take my pH to high end of what is recommended? Wait for it to rise naturally?

Here are today's numbers:
CSI - -.45
FC - 4.5
CC - .5
pH - 7.4
TA - 70
CH 400

 

[RussellC]

Your CSI is always going to dip temporarily when you are trying to lower TA because you are getting that pH below range. It is OK for short periods of time. Once you get things balanced you will be good to go.

 

[Texas Splash]

Humm. Something's not adding-up right. When I use the Poolmath calculator for your 28K pool, and use 7.4, 70, and 400 as my numbers, I get a CSI of "-0.18". You might want to verify on your end as well.

 

[QingGuy]

Humm. Something's not adding-up right. When I use the Poolmath calculator for your 28K pool, and use 7.4, 70, and 400 as my numbers, I get a CSI of "-0.18". You might want to verify on your end as well.

Hmmmm, maybe a data entry error. I'll look at it when I'm home tomorrow. Thanks for pointing this out!

 

[JoyfulNoise]

Humm. Something's not adding-up right. When I use the Poolmath calculator for your 28K pool, and use 7.4, 70, and 400 as my numbers, I get a CSI of "-0.18". You might want to verify on your end as well.

Hmmmm, maybe a data entry error. I'll look at it when I'm home tomorrow. Thanks for pointing this out!

TS,

You're not accounting for salt. When you add 3600ppm (average for his SWG), you get the correct CSI that QingGuy quotes.

QingGuy,

Now that you lowered TA, allow your pH to drift up to 7.6-7.8 and hold it in that range. Do not add any acid until your pH rises above 7.8 and only lower it down to 7.6. See what your acid addition frequency is.

Also, can you post test results for your fill water? That's important too.