Quote Originally Posted by jereece
This data is very interesting. Thank you for doing this research.

I downloaded the Excel spreadsheet and began playing with it. Only problem is when I click on the "Calculate pH/TA" button, I get an error message "Compile Error - Can't find project or library". When I click OK, it takes me to the debugger. It highlights "SolverReset" in the "Sub Calculate_pH_TA_FC_CYA()" section of Module1. Any idea what the problem is on my end?

Thanks,
Jim
Jim,

You might have downloaded the spreadsheet before I edited my post to give the following instruction:

The “Pool Equations” spreadsheet uses macros to compute the reverse computations (calculating pH and alkalinity when you add chemicals) so to get this to work on a PC using an older version of Excel you will need to go into your “Tools – Add-Ins...” menu in Excel and check the box for “Solver Add-In”.

The error you are getting sounds like the Solver toolpak is not installed so try adding it in as I describe above and let me know what happens.

Richard