Question about pool calculator

[mynewpool]

I have a question. I have found that using the part at the bottom of the pool calculator effects of pool calculator is a lot better for me. When I fill in the top and say I want to change pH level from 7.8 to 7.4 and I feel out all other test with the same number in now and target, I will get a different amount in the top part vs bottom part in the effects section.

In the top part I will only want to affect pH and drop it to 7.4 from 7.8, 37 oz to be exact. In the top part though it will say add like 70 oz of acid, which in the bottom part says it will drop about .76.

Am I doing something wrong here.

Is there anyone else who uses just the bottom part when you need to change individual stuff like pH levels or chlorine?

Thanks.

 

[frustratedpoolmom]

The "effects" section doesn't take into account your current TA level so the amounts will be different.
Use the top section to determine that dosage properly.

 

[mynewpool]

The "effects" section doesn't take into account your current TA level so the amounts will be different.
Use the top section to determine that dosage properly.

In the top section though, if I put TA the same in both columns, then that should not affect the acid addition right?

 

[frustratedpoolmom]

Right, if you aren't adjusting TA, just put the same number in both.

 

[chem geek]

The amount of acid in the top section will vary depending on the TA level in the top section (even when the TA is the same in both columns; it mostly uses the Now column) AND on the starting and ending pH. The bottom section on the effect of adding chemicals does not take into account a different TA level nor a different starting and ending pH. The top section is the more accurate one.