Pool Math Desk Top Version

[Taylor1584]

Am I interpreting Pool Math correctly.
FC 9.5.
CC 0
Ph 8.0
TA 70
CH 250
CYA 70 (down from opening late April @ 120)
Salt 1200
Temp 91
CSI 0.17

My Ph is 8.0 and wanting to lower to 7.6
Desktop pool math says to add 9.1 oz of 31.45% muriatic acid. I have use this calculator for years. This is a new to me pool so I am testing, adding the recommended amount, waiting about 20 min. and retesting. My results are not even close. I retest in another 20 minutes thinking it hasn't mixed yet and same thing. Note, I have dialed in the gallons of this new to me pool with the liquid chlorine additions and they are spot on.

I started looking at the calculator "Effects of Adding Chemicals".
It says adding 9.1 oz. of MA will lower Ph by 0.18.
That isn't enough to get me from 8.0 to 7.6 Ph.
I adjust the Adding Chemicals until I got the change I wanted. to lower Ph by 0.4 , and it says I have to add 20 oz. of MA which is a big difference from what the calculator suggests.

Am I using the calculator correctly and if so why does the effects of adding chemicals differ?

I must be doing something wrong.

 

[HermanTX]

Please clarify - your signature states 12,000 gals but your data on left side under your name states 20,000 gals. Is one system using different volumes?

Also, your PM logs that are linked state 11,500 gals.

 

[Taylor1584]

Please clarify - your signature states 12,000 gals but your data on left side under your name states 20,000 gals. Is one system using different volumes?

Also, your PM logs that are linked state 11,500 gals.

ACK, thought I changed everything to the new to me pool. It's 12,000 gallons in NW Arkansas. Will change right away. Thank you for the heads up.

Chris

 

[Taylor1584]

Am I interpreting Pool Math correctly.
FC 9.5.
CC 0
Ph 8.0
TA 70
CH 250
CYA 70 (down from opening late April @ 120)
Salt 1200
Temp 91
CSI 0.17

My Ph is 8.0 and wanting to lower to 7.6
Desktop pool math says to add 9.1 oz of 31.45% muriatic acid. I have use this calculator for years. This is a new to me pool so I am testing, adding the recommended amount, waiting about 20 min. and retesting. My results are not even close. I retest in another 20 minutes thinking it hasn't mixed yet and same thing. Note, I have dialed in the gallons of this new to me pool with the liquid chlorine additions and they are spot on.

I started looking at the calculator "Effects of Adding Chemicals".
It says adding 9.1 oz. of MA will lower Ph by 0.18.
That isn't enough to get me from 8.0 to 7.6 Ph.
I adjust the Adding Chemicals until I got the change I wanted. to lower Ph by 0.4 , and it says I have to add 20 oz. of MA which is a big difference from what the calculator suggests.

Am I using the calculator correctly and if so why does the effects of adding chemicals differ?

I must be doing something wrong.

So just for the heck of it this morning I dosed MA based on Effects of Adding Chemicals instead of the pool math calculation. I kept changing the amount until it read it would reduce the Ph by 0.4, added that amount and waited an hour to retest. Result Ph is right where I targeted.

When using pool math for all the other chemicals it is spot on. I had this problem with my other pool and Ph also. I would add the calculator recommended amount, wait 30 min, test and always be short, resulting in retest, make additions, retest.

Not sure if it is user error. I am going to test over the next week to see if it repeats itself. The pool, came with house I just bought, was replastered 1 yr. ago.