muratic acid recommendations in pool math app

[abfab]

My test the other day showed ph=8 (max for my test kit). 1 drop of reagent lowers it to 7.4. The booklet in the kit says to add 286ml of 20 Baume for 40,000 liter pool. The app gives me very different instructions. When I input TA=70 and Borates=90 it tells me that I need to add 2.3 liters to get 7.5 ph (my target). Without entering TA and BOR it tells me I only need only 62ml. Why is there such a big discrepancy between the app and the test kit? Am I looking at something wrong? I verified that I have 47,000 listed in the app.

I normally add about 300ml but thought I wasn't adding enough so I added 1 liter to see the effect. When I checked after an hour of pump running on low it was at 7.5. The next afternoon it was at 7.4.

 

[mknauss]

Borates have a large effect on how much acid is needed to move pH.

You have added Boric Acid and do have a test showing the 90 ppm of borates?

 

[abfab]

Borates have a large effect on how much acid is needed to move pH.

You have added Boric Acid and do have a test showing the 90 ppm of borates?

I never adjust my borate levels and never add borax. I only tested because the app asked about it when determining muriatic acid amount.

 

[mknauss]

How did you test the borates?

 

[abfab]

How did you test the borates?

oops. I was confusing the CH test with Borates! When I remove that from the app it still tells me that I should be adding 1.7 liters, which based on my test is still too high.

 

[mknauss]

I put your info into PoolMath. To lower your pH from 8 to 7.5, with a TA of 70, and 40000 liters, I get you need to add 317ml 31.45% muriatic acid.

 

[abfab]

I put your info into PoolMath. To lower your pH from 8 to 7.5, with a TA of 70, and 40000 liters, I get you need to add 317ml 31.45% muriatic acid.

I am getting the 316ml now too. I'm not sure what I changed or what I did but it seems to be working as expected now. weird. thank you.