Which one should I adjust first

[MarkC]

Add half that then retest the pH in a few hours if you need more repeat.

[prh129]

A 24' round AG pool should only be around 13500 gallons, not 17000.

If you test a couple hours after you add the acid, you will find out if it is enough. Testing is the key - you need to know where you are and where you want to go before you start adding chemicals. It's better to add less and move closer to your target than to add too much and overshoot (for everything - pH Cl Alk CYA etc.)

Peter