Why can't I get my ph down?

[steelman93]

Hello,

I have a salt pool, plaster finish and from the time I have owned it I cannot keep the PH below 8. I tested twice this past weekend, once with chemicals which shows it over 8.2 (the max of the reading. I also have an electronic tester which showed 9.1, and I do believe that. I can add acid all day long and within a day or two it increases. I know that salt pools tend to increase PH, but this is more than seems normal.

I also had a jump in alkalinity recently, not sure why.

Can someone give me pointers on what I am doing wrong. Also would like input into salt testing. I have tried strips, the chemicals and also the unit self's reading and there are wild variations. What is in my logs is what I get using chemicals....the unit says I am around 2900 and the strips say 4000.

Here are my logs:

PoolMath Logs

I am so so on entering additions. I try to log them....but I may miss some so take those with a grain of salt.

 

[proavia]

Since the pH appears to be above 8.0, use PoolMath to determine the amount of acide to lower the pH 0.4. Add that amount and retest after 15 minutes with pump running. Continue this testing and adding until you get the pH to the desired reading in the 7's.

Your TA of 120 is causing the pH to rise quickly. Once your pH is in the 7's, work on lowering the TA to about 60 or70. This will slow the pH increase.

Lower Total Alkalinity

A lower Total Alkalinity level can help a pool owner stabalize their pH increase. We'll explain how to lower TA with a little help from muriatic acid.

www.troublefreepool.com

As for salt testing, use the Taylor K-1766 salt test kit. Salt test strips are a guess and the SWG reading isn't a true salt test, it's more of a conductivity test.

Use of a Speed Stir or Smart Stir will help your test results to be more accurate and repeatable.

 

[reggiehammond]

Any water features? Fountains, water falls?
What's the TA and pH of your source water?

Controlling TA will have a big effect on your pH control. You want to focus on this as it relates to CSI to protect your SWCG from scale.

 

[steelman93]

Since the pH appears to be above 8.0, use PoolMath to determine the amount of acide to lower the pH 0.4. Add that amount and retest after 15 minutes with pump running. Continue this testing and adding until you get the pH to the desired reading in the 7's.

Your TA of 120 is causing the pH to rise quickly. Once your pH is in the 7's, work on lowering the TA to about 60 or70. This will slow the pH increase.

Lower Total Alkalinity

A lower Total Alkalinity level can help a pool owner stabalize their pH increase. We'll explain how to lower TA with a little help from muriatic acid.

www.troublefreepool.com

As for salt testing, use the Taylor K-1766 salt test kit. Salt test strips are a guess and the SWG reading isn't a true salt test, it's more of a conductivity test.

Use of a Speed Stir or Smart Stir will help your test results to be more accurate and repeatable.

Thanks for the reply .

When I say chemicals, I am using that exact kit for salt testing. I also have a smart stir. For some reason the silver nitrate contaminated the stirrer and turned it black, so I use that one exclusively for salt.

On the alkalinity.....when mine was 60 or 70 I still had problems with PH.

 

[proavia]

Add that test kit to your signature, and the Smart Stir too.

What is the pH, TA and CH of your fill water?

At lower TA - 60-70 instead of 120 - your pH rise will slow.
Your SWG doesn't cause pH to rise much quicker than using liquid chlorine. If you were using tabs before conferting to SWG, the rise in pH with the SWG will be more pronounced as the tabs are acidic.

Be sure to track CSI in PoolMath and keep the CSI between 0.00 and -0.30. Slightly negative is recommended. This will minimize scaling on the SWG.

 

[steelman93]

Add that test kit to your signature, and the Smart Stir too.

What is the pH, TA and CH of your fill water?

At lower TA - 60-70 instead of 120 - your pH rise will slow.
Your SWG doesn't cause pH to rise much quicker than using liquid chlorine. If you were using tabs before conferting to SWG, the rise in pH with the SWG will be more pronounced as the tabs are acidic.

Be sure to track CSI in PoolMath and keep the CSI between 0.00 and -0.30. Slightly negative is recommended. This will minimize scaling on the SWG.

test kit and stir added.

on the fill water....I honestly don't know....but most of my fill comes from rain. I have an automatic level system with an overflow, but I don't think it adds much. At least I don't see it in my water bill. I can fill a bucket and test that though to see what it is.

 

[steelman93]

Any water features? Fountains, water falls?
What's the TA and pH of your source water?

Controlling TA will have a big effect on your pH control. You want to focus on this as it relates to CSI to protect your SWCG from scale.

I have a spa with an overflow and a waterfall, but I don't use waterfall much. However, the overflow is always going.

 

[mknauss]

but most of my fill comes from rain

The TA in your pool water has to come from somewhere. It is either added via the TA in your fill water, or it is added chemically.

 

[proavia]

Test the water coming directly out of of the tap nearest where your autofill is hooked up.
Don't fill a bucket and then test that as that could sway the results.

If the spillway is always on when the pump is on you are aerating the water, thereby increasing the pH.
Does your pool have automation?

As Marty indicated, the TA has to come from somewhere.
What chemicals have you added? Baking soda? Alkalinity up? Any magic pool store potions?

 

[Toxophilite]

Check your fill water TA. Notice mine in signature line from well water in your part of world

 

[steelman93]

a few updates......

Last night I followed @proavia suggestion...added acid waited 15 minutes, tested, rinse and repeat. I started at a 8.2 ph, added a quart, tested at 7.8, added a quart, tested at 7.6 and then added another quart of acid. This morning I got up and tested it at 7.8 and then when I got home it tested at 8.1

My spillway is always on. The pool is automated and honestly, I am not sure how to turn that off. I think I would need to do it manually by valving off the hot tub.

I tested my fill water I 50 hardness, 1.5 free chlorine and 30 alkalinity. I do not use any chemicals other than calcium hardness increaser, CYA and salt. No clarifiers, alkalinity increasers, shock etc. I have a small yard so I do get mulch and clippings in the pool every time I mow, but I don't think this would increase the alkalinity much.

Based on how slow the ph was coming down last night, I figured I need at least 2 gallons in one night to get it down to a 7. Is that too much? Its an 11000 gallon pool

 

[PoolStored]

a few updates......

Last night I followed @proavia suggestion...added acid waited 15 minutes, tested, rinse and repeat. I started at a 8.2 ph, added a quart, tested at 7.8, added a quart, tested at 7.6 and then added another quart of acid. This morning I got up and tested it at 7.8 and then when I got home it tested at 8.1

My spillway is always on. The pool is automated and honestly, I am not sure how to turn that off. I think I would need to do it manually by valving off the hot tub.

I tested my fill water I 50 hardness, 1.5 free chlorine and 30 alkalinity. I do not use any chemicals other than calcium hardness increaser, CYA and salt. No clarifiers, alkalinity increasers, shock etc. I have a small yard so I do get mulch and clippings in the pool every time I mow, but I don't think this would increase the alkalinity much.

Based on how slow the ph was coming down last night, I figured I need at least 2 gallons in one night to get it down to a 7. Is that too much? Its an 11000 gallon pool

Something is adding TA to your pool. Likely your fill water and evaporation...do you have an autofill?


If you note in pool math, there is a not about making adjustments to pH. Do it in .4 increments first to see how pool reacts. Better to do this way that one fell swoop 2 gallons.. Could end up crashing pH. Pool math works, for pH, in a narrower range of parameters.

The spillway is causing aeration which will raise pH. As you add acid, it will bring down pH AND bring down TA. When your TA is about 60-8, your pH rise should slow, even with the spillway. Would be good to find a way to reduce the spillway run, if you want to reduce MA addition frequency.

 

[proavia]

The pool is automated ...

What automation system does your pool have - manufacturer and model number?

Most automation systems have a way to program spillway or spill over mode. It can be set to come on for 10-15 minutes twice daily to keep the spa chlorinated. If your automation system has this and you program it, you can close the "make up" line that is allowing the spillway to flow any time the pump is on and helping to cause your pH climb due to constant aeration.

 

[steelman93]

What automation system does your pool have - manufacturer and model number?

Most automation systems have a way to program spillway or spill over mode. It can be set to come on for 10-15 minutes twice daily to keep the spa chlorinated. If your automation system has this and you program it, you can close the "make up" line that is allowing the spillway to flow any time the pump is on and helping to cause your pH climb due to constant aeration.

I have a Jandy RS-PS6 Pool & Spa Combination, with a Jandy 6614-AP-L Power Center and use the Iaqualink version 6.7 app.

Another question is roughly how many hours a day should the pump be on? I have a hayward 1 horse pump and the pool is small.

Thanks

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[steelman93]

Something is adding TA to your pool. Likely your fill water and evaporation...do you have an autofill?
View attachment 480438

If you note in pool math, there is a not about making adjustments to pH. Do it in .4 increments first to see how pool reacts. Better to do this way that one fell swoop 2 gallons.. Could end up crashing pH. Pool math works, for pH, in a narrower range of parameters.

The spillway is causing aeration which will raise pH. As you add acid, it will bring down pH AND bring down TA. When your TA is about 60-8, your pH rise should slow, even with the spillway. Would be good to find a way to reduce the spillway run, if you want to reduce MA addition frequency.

for clarity I meant adding acid quart at a time, but over a period of time, but based on past experience it will take several gallons on the same day.

I do have an autofill, but tested the water last night...it is only 30 alkalinity

 

[proavia]

I have a Jandy RS-PS6 Pool & Spa Combination, with a Jandy 6614-AP-L Power Center and use the Iaqualink version 6.7 app.

Maybe @ajw22 or someone else well versed on Jandy automation will stop by to confirm whether or not your system can be programmed for a proper spillway mode.

Post a few pics of you equipmemt pad so we can see all the plumbing and valves.

 

[ajw22]

I have a Jandy RS-PS6 Pool & Spa Combination, with a Jandy 6614-AP-L Power Center and use the Iaqualink version 6.7 app.

​

See Jandy Aqualink RS - Further Reading for how to enable SPILLOVER mode with dipswitch #3 making AUX3 your SPILLOVER control.