CYA is High (120+) PH is not going up

[Jschway]

PH test with Taylor test kit is bright yellow...
CYA is 120 (I cut the sample water in half with fresh waster and CYA said 60 so I doubled it...)
TA is 0

I have added suggested amounts of baking soda and run the fountain Jets...

Why is my PH and TA not coming up?
Does a high CYA level effect PH and TA tests?

I'm draining and refilling smaller amounts trying to get my cya down. Then add the baking soda my next test still shows TA and PH bottomed out. I have done this twice.

 

[Jschway]

For context:
Not my pool
40k
Chlorine
Vinyl

 

[Newdude]

I'm draining and refilling smaller amounts trying to get my cya down

You need to drain at least half the water. Subsequent drains remove new water with the old, so each round becomes less efficient. With large drains it's better, such as two 50% drains remove 75% of the water instead of 100%, but with small drains you're just spinning your wheels.

There's a couple ways to go about it here:

Draining - Further Reading

www.troublefreepool.com

 

[Mdragger88]

Its not the cya - it’s the acidic pucks &/or “shock” they have been using that have tanked the ph & ta.
Do the no drain exchange
Section 3.5

Draining - Further Reading

www.troublefreepool.com

& get the cya down by 50%
The new fill water will bring up the ph & ta

 

[Mdragger88]

Also test the ph & ta of the fill water so you know what you’re working with.
Is it municipal water?

 

[Mdragger88]

For reference

Use
PoolMath effects of adding

 

[Jschway]

Thank you! I wanted to make sure that the high CYA in the water was not negatively affecting other test results.

 

[Mdragger88]

Home Depot in olive branch has pumps you can rent or any submersible pump will work so long as you can adjust the fill water to the same flow amount. Don’t drain below 18 inches in the shallow end and if there’s high ground water in the area stick with the no drain exchange

 

[Jschway]

For reference
View attachment 515052
Use
PoolMath effects of adding

This does not make sense with the "effect of adding" in the pool math app..

10 LB of Borax 20 Mule = 0.4 PH / 7.1TA
10 LB of Washing Soda = 0.9PH / 26 TA
10 LB of Baking Soda = 0.0 PH / 16 TA
10 LB Borax = 0.4 PH / 7.1 TA

What am I doing wrong?

 

[DrewLG]

You need to drain at least half the water. Subsequent drains remove new water with the old, so each round becomes less efficient. With large drains it's better, such as two 50% drains remove 75% of the water instead of 100%, but with small drains you're just spinning your wheels.

Not EXACTLY spinning your wheels...

Of course it's most efficient to cut CYA in half by doing a single 50% drain and refill. But if you can't do 50% at a time, doing less isn't as inefficient as most people seem to believe. For the 40000-gallon pool in question, to reduce CYA from 160ppm to 80ppm:

Draining 20% at a time, you'd do three 8000-gallon drain/refill cycles for a total of 24000 gallons (around 80% efficiency).

Draining 10% at a time, you'd do seven 4000-gallon drain/refill cycles for a total of 28000 gallons (around 75% efficiency).

And the efficiency doesn't change much for smaller drains, so even with 1% drains (400 gallons at a time), you'd still only have to drain/refill a total of around 28000 gallons.

 

[Newdude]

Not EXACTLY spinning your wheels...

Agreed. Poor choice of words.

But even at the 20% each drain example, losing 20% efficiency is huge for people on wells, with expensive fill water and/or those with poor draining paths/options.

At the 10% each drain example it loses 40% efficiency, needing to remove and fill 28k gallons to actually exchange 20k.

Smaller drains are even more inefficient and turn it into a long drawn out process.

It is what it is sometimes with poor drain choices, or a well that needs frequent rest periods. But when possible, it's best to do more draining in less rounds.

 

[DrewLG]

But even at the 20% each drain example, losing 20% efficiency is huge for people on wells, with expensive fill water and/or those with poor draining paths/options.

Yes, no question that throwing away 20% more water can be painful. I'm supplied by a tiny neighborhood water utility with small tanks, so fill water is expensive and available only in relatively small volumes, and I'm on a septic system so there's no good way to drain a lot of water at a time. When I lowered my CYA from 180 to 60 shortly after moving here, I had to do it in 10% steps, so I have first-hand familiarity with the pain.

It is what it is sometimes with poor drain choices, or a well that needs frequent rest periods. But when possible, it's best to do more draining in less rounds.

Agree completely. I just wanted to point out that it's not impossible to lower CYA -- even by as much as 50% -- with tiny drain/refill cycles if that's your only option. You still have to accept that you'll waste some large fraction of the water you're replacing, but the waste isn't as large as people seem to think.

 

[mknauss]

Whatever you do, if your TA is zero, and you have a vinyl liner, you need to get the water exchanged or start adding baking soda. The vinegar in your pool is destroying the liner.

 

[Mdragger88]

This does not make sense with the "effect of adding" in the pool math app..

10 LB of Borax 20 Mule = 0.4 PH / 7.1TA
10 LB of Washing Soda = 0.9PH / 26 TA
10 LB of Baking Soda = 0.0 PH / 16 TA
10 LB Borax = 0.4 PH / 7.1 TA

What am I doing wrong?

I am not sure I follow?
Those are the effects each of those additions would have. I checked with pool math myself.
Pick one & use it whichever you have on hand is fine. You need ta above 40

 

[JamesW]

The TA can be below 0, so you might add 50 ppm and still see no change if the TA is -80.

I would add 100 ppm of TA with baking soda and then see what the TA and pH are.

The high CYA interferes with the TA reading.

Is this the same person or do you have a bunch of friends with zero TA?

Helping a buddy with his pool

Should I tackle the CYA or the TA first? TA says I should add 41 lb of soda!! Any guesses on how much muriatic acid I'll probably need to add? ========================================== ------------------------------------------ Build Type: Vinyl Volume: 44000 gallons...

www.troublefreepool.com

When the TA is red, the TA is 0 or negative.

To calculate the actual TA, I use R-0006 base demand to titrate from red to green and then multiply the result by 6.3 to see how negative the TA is.

 

[Jschway]

I am not sure I follow?
Those are the effects each of those additions would have. I checked with pool math myself.
Pick one & use it whichever you have on hand is fine. You need ta above 40

I was quoting the graphic that someone posted above. . The picture did not show up.

 

[Mdragger88]

I was quoting the graphic that someone posted above. . The picture did not show up.

I understand- is there something you’re not understanding about it?
10 LB of Borax 20 Mule = 0.4 PH / 7.1TA
Big ph/small Ta change
10 LB of Washing Soda = 0.9PH / 26 TA
Bigger ph/Bigger TA change
10 LB of Baking Soda = 0.0 PH / 16 TA
Small ph/big ta change
Use the one you have to get you what you need . You need Ta above 40 & ph in the 7’s
Baking soda or washing soda are good options here.

 

[JamesW]

When the pH is really low, adding baking soda has a big impact on the pH because it depends on how much of the bicarbonate converts to carbon dioxide.

The below graph shows how much the pH is impacted by adding baking soda because it shows how much gets converted to carbon dioxide.

The reference to little effect is when the pH is over 7.5, but you don't need to raise the pH in that case anyway.

Anytime you need to raise the pH, baking soda will work.

I would never use sodium carbonate (pH increaser aka soda ash).

This shows how much of the added baking soda stays as baking soda and the rest converts into carbonic acid/dissolved carbon dioxide.

All baking soda (Hydrogen carbonate) that picks up a hydrogen ion increases the pH.

Baking soda only has a small effect on the pH when the pH is already high because only a tiny amount of baking soda converts to carbonic acid when the pH is high.

HCO₃^- + H⁺ --> H₂CO₃ --> H₂O + CO₂

pH..........%baking soda

6.35............50.00

6.5..............58.55

6.6..............64.01

6.7..............69.12

6.8..............73.81

6.9..............78.01

7.0..............81.71

7.1..............84.90

7.2..............87.62

7.35...........90.91

The Y axis is the percentage of baking soda that converts into carbon dioxide.

The X axis is the pH.

y = 100-(100/(1+10^(6.35– x))), x from 4 to 8 - Wolfram|Alpha

Wolfram|Alpha brings expert-level knowledge and capabilities to the broadest possible range of people—spanning all professions and education levels.

www.wolframalpha.com

As you can see, most of the bicarbonate converts into carbon dioxide when the pH is below 6.35.

 

[JamesW]

If the pH is over 7.6, then less than 5% of the baking soda converts to carbon dioxide.

However, if the pH is over 7.6, then the TA is probably fine.

In my opinion, there is never a reason to "Raise" the pH directly.

If the TA is good, the pH will be good.

If the pH is too low, the TA is too low.

If the pH is too high, then the TA is probably too high.

 

[Mdragger88]

James pointed out great info about the science
Use the baking soda until you get a readable ta in the 40’s/50’s. Just keep doing what
PoolMath says until you get a measurable value - using current of zero & target of 40.



The others & the graphic are good to have available for when ph& ta aren’t so critically low like you have now.
I am curious too if this is the same pool from the other post.