Dear Chem Geek, I've downloaded a copy of your PoolEquations.xls file and as a non practicing Chemical Engineer and pool owner I am beyond impressed. If I may ask a few questions:
1) is there a thread with basic instructions?
2) if I press either the "Calculate pH/TA" or any fo the "Calculate" buttons for that matter I can tell that it is going through the iterations but when finished it simply sets the Goal equal to the Intitial and then all the necessary additions are zero. I assume something is malfunctioning?