Impact of adding Cya factored into Ph?

[Sdhb]

Trying to understand how the app handles impact of adding CYA to PH. Looking at my attached readings, Pool math is calling for me to add 545g of dry acid to lower ph from 7.8 to my target of 7.65.

It is also calling for me to add 293g of CYA to hit my CYA target. Adding that amount of CYA should also drop ph by -.1 according to Affects of Adding.

I assumed that would be factored in such that Pool math would call for less dry acid to account for the impact of the CYA its also recommending to add..

But it seems not. To validate this, I adjusted my CYA target in the app way upwards so that the app recommends adding tons of CYA, enough to completely drop PH to zero.. But the app still recommends to add the same amount of dry acid. So is each "box" in the app not taking into account what is being added in other boxes at the same time?

Sorry if that's not clear.

 

[mknauss]

Your pH is fine. The CYA will drop it a bit. No need to bother with using acid.

Also, never use dry acid with a SWCG. The sulfates destroy the rare earth metals on the plates of the SWCG.

 

[Sdhb]

Your pH is fine. The CYA will drop it a bit. No need to bother with using acid.

Also, never use dry acid with a SWCG. The sulfates destroy the rare earth metals on the plates of the SWCG.

Thanks. I guess the intent of my question was more general though. Forgetting about my specific circumstance - does the app not take into account the impact of multiple additions recommended at the same time?

If not, isn't that potentially problematic in circumstances where large additions are being called for.. such as opening?

 

[mknauss]

does the app not take into account the impact of multiple additions recommended at the same time?

No. It is a calculator and data storage device. You must manage the pool water chemistry.

 

[ajw22]

Pool Math does not know how multiple chemical additions interact.

 

[Sdhb]

Okay thanks! If I remember correctly, I read that poolmath does take the inputted TA values and calculates adjusted alkalinity in the background, which it uses to then make chemical recommendations.

So if that's true, then atleast the TA box is observant of other inputs. Unless I have that wrong.

 

[mknauss]

It does take into account the non carbonate alkalinity when necessary for calculations.

 

[Sdhb]

When necessary for calculations, as in when determining if an addition is recommended?

For example my TA is 70, which is in range so no addition recommended. However with PH of 7.8 and CYA of 70, isn't the adjusted/carbonate alkalinity actually closer to 45? Which means it's actually outside of the range now and presumably would need to be raised up? Ty

 

[mknauss]

TA is TA. The adjustment is for calculation of acid needed for a pH change and CSI.