pH rising super fast

[haxorcize]

TLDR: my pH is rising super fast. My pool should be pretty balanced. I suspect the TA.

Metrics:
22000 gallon pool. Built-in spa with spillover. Sun shelf with 2 returns aimed upwards.
CYA 50
Chlorine 6
TA 40
Calcium Hardness 400
CYA 50ppm

Background:

[1] I took the pool from algea to super clear following the PoolSchool's amazing content.
Fixed CYA, pH, did SLAM, everything is clear and pretty, now I'm in maintenance mode.
Only using liquid chlorine, checking daily.

[2] My chlorine levels drops at a reasonable rate and I add more liquid chlorine every few days.

[3] My biggest problem is my pH - it keeps rising from 7.2 to 8+ (dark pink) in a matter of 2 days.
I slowed down the pool pump speed, and turned off the returns in the sun shelf that used to create a fountain effect,
so all my water is gliding along (no splashes), thus minimizing aeration.

[4] I suspect my TA levels are not good (already ordered bags of baking soda), but I am not sure.
I've seen posts saying TA being too low will drag pH down, but my TA is low and my pH is not going down at all.

I'd LOVE to figure out pH and make it more stable. Hate pouring all this muriatic acid.

 

[Rancho Cost-a-Lotta]

Your TA is too low and is likely causing the pH swings. Increase TA to 60 ppm. This level will still help to control pH rise.

 

[PoolStored]

Your TA is too low and is likely causing the pH swings. Increase TA to 60 ppm. This level will still help to control pH rise.

@Rancho Cost-a-Lotta is right, raise TA to 60.
Low TA is not causing the swing. The fact that you are driving pH down to 7.2 is cause the pH rise.
After you raise TA to 60, leave pH alone, let it rise. It should be fairly stable around 7.8-8. Don't drive pH back down below 7.8...Driving pH down to 7.2 caused your TA to drop below target.

 

[pjt]

my pH is rising super fast.

What specific test kit are you using?

I suspect my TA levels are not good

Assuming you're using a recommended test kit, are you continuing to add drops until there's no additional color change? It typically takes ~3 more drops after the initial color change.

already ordered bags of baking soda

Under normal circumstances, a non-trichlor pool should never need baking soda.

I've seen posts saying TA being too low will drag pH down

Having TA on the low end will slow down pH rise, which is usually the desired result. TA of 50 or above is perfectly fine.

Where are you in Texas? What's the TA of your fill water?

TA - Further Reading

www.troublefreepool.com

PH TA Relationship - Further Reading

www.troublefreepool.com

 

[JamesW]

Get PoolMath and track CSI.

If the CSI is good, you can probably leave the pH and TA alone.

Don't let the pH go over 8.3.

Show your pH test as I suspect that you are probably reading it higher than actual.

Maybe get a pH meter to be sure.

 

[JamesW]

PoolMath

 

[JamesW]

Your TA is too low and is likely causing the pH swings. Increase TA to 60 ppm. This level will still help to control pH rise.

Increasing the TA will not help.

It will only increase the amount of carbon dioxide and that will increase pH rise.

Basically, stop adding acid unless the CSI is over 0.2 or if the pH is over 8.3.

If you add acid, only add enough to get the pH to about 8.1 or the CSI to about 0.0.

 

[JamesW]

Low CSI can cause plaster to dissolve and this will cause the pH, TA and calcium levels to rise.

If the calcium hardness and TA both rise equally with nothing added, then you might have plaster dissolving.

This can happen with bad plaster, new plaster, old plaster or plaster that was recently acid washed.

Typically, this is accompanied by seeing plaster aggregate on the floor or in cleaner bags.

 

[JamesW]

Keep the CSI as close to 0.0 as possible.

 

[PoolStored]

Keep the CSI as close to 0.0 as possible.

Yep.

 

[JamesW]

Deleted.

 

[JamesW]

TA 40
Calcium Hardness 400
CYA 50ppm

Increasing the TA to 60 almost doubles the carbonate alkalinity and puts the CSI at +0.3.

I would go to 50 TA and then balance the CSI to 0.0.

Cyanuric Acid correction factor based on pH.

40 - (50 x 0.36) = 22.

50 - (50 x 0.36) = 32.

60 - (50 x 0.36) = 42

pH........CF

7.0.......0.22

7.1.......0.24

7.2.......0.26

7.3.......0.28

7.4.......0.30

7.5.......0.32

7.6.......0.33

7.7.......0.34

7.8.......0.35

7.9.......0.36

PoolMath

Discover the calculator behind the perfect pool, PoolMath. Dealing with pools has allowed TFP to become the original authors of the best calculator on the net.

www.troublefreepool.com

 

[JamesW]

Is the calcium hardness increasing on its own?

What is the salinity?

What is the water temperature?

Are you getting plaster aggregate on the floor?

 

[haxorcize]

What specific test kit are you using?

TF-Pro

Assuming you're using a recommended test kit, are you continuing to add drops until there's no additional color change? It typically takes ~3 more drops after the initial color change.

I see one drop making it starting to become red but mostly green. Another drop makes it almost colorless. And then I do another drop when the entire container becomes red. (I’m using the magnetic stirrer). So I think I’m doing it according to the TF-Pro’s instructions - but once it’s all red I never put another drop.

Where are you in Texas? What's the TA of your fill water?

Cedar Park, just north of Austin.
My autofill float valve broke so I turned of the fill water in the past couple of weeks - so I don’t think that’s the source of my issues..?

Don't let the pH go over 8.3.

Show your pH test as I suspect that you are probably reading it higher than actual.

Maybe get a pH meter to be sure.

Agree it’s hard to read, but when it’s 7.2-7.5 after lowing it I can clearly tell. And a day later when it’s 7.8 I can tell. But once it goes purple/pink it’s hard to tell just how much above 8 it is. I wish there was an accurate drop test for that. Any recommended pH meters?

CSI is -1.25 if pH is 8. CSI is -.95 if pH is 7.2...OP is no where close to 0. This is assuming salt is 0, which is not likely.

OP should test and report salt with a Taylor K-1766.

With 1000ppm Salt (reasonable), OP's CSI is -.1, at pH 7.8.

Again, even with a reasonable salt level, and a TA of 60, OP should not be driving pH down to the low 7s. Let it be around 7.8 - 8.0. Driving pH down so low is causing the pH rise.

Can the TF-Pro make that test or do I need another kit? (I’m don’t have an SWG)

PoolMath

I am using and loving it. Also did the subscription so I can track all the measurements.

——-

So if I recap - you’re recommending I increase my TA to 50-60, get a pH meters, and let it hover around 7.8-8 and see if it stays there reasonably.
Also - I should compute my CSI score? (Never did that before).

 

[JamesW]

So if I recap - you’re recommending I increase my TA to 50-60, get a pH meters, and let it hover around 7.8-8 and see if it stays there reasonably.
Also - I should compute my CSI score? (Never did that before).

Yes, increase TA to 50 or 60.
Get a K-1766 test kit for salt.
Turn on track CSI in Poolmath.

 

[JamesW]

PC60 Premium Multiparameter (pH/EC/TDS/Salinity/Temperature) Pocket Tester/Meter Kit-Apera Instruments

The Apera Instruments PC60 Multi-parameter Tester/Meter simply tests pH/EC/TDS/Salinity/Temperature for regular aqueous solutions such as hydroponics, aquaculture, pools& spas, tap/drinking water, water treatment, cooling towers, etc.

aperainst.com

This will measure pH and Salinity.

Balance CSI at 0.0 using the pH.

I would be ok with a pH up to 8.3 as long as I was sure that I had an accurate number.

 

[JamesW]

I see one drop making it starting to become red but mostly green. Another drop makes it almost colorless. And then I do another drop when the entire container becomes red.

Is that 3 drops total?

 

[haxorcize]

Is the calcium hardness increasing on its own?

Haven’t tested in a while. I’ll check and report back.

What is the salinity?

Will check once I get a salt test kit

Are you getting plaster aggregate on the floor?

Don't think so, at least nothing noticable. It's a 3 year old pool, has pebble-tech plaster.

Yes, increase TA to 50 or 60.
Get a K-1766 test kit for salt.
Turn on track CSI in Poolmath.

Thanks everybody - check all of these and report back.

 

[haxorcize]

Is that 3 drops total?

Total was 4 drops actually.
First drop - still green
Second drop - still green (but see red in the middle)
Third drop - not green nor red
Fourth drop - all red

 

[proavia]

Total was 4 drops actually.
First drop - still green
Second drop - still green (but see red in the middle)
Third drop - not green nor red
Fourth drop - all red

Keep adding drops until the color no longer changes. Subtract the last drop that doesn't change the color any further.
Do this for both the TA and CH tests.

Some say the TA test will turn "barbie pink".