There is no such thing as a meaningful “one-size-fits-all” spreadsheet for calculating G values and detention times for jar tests. Yours should be unique to your plant, as this one here is. I made it for a client. It has their exact basin dimensions, HP capabilities, lookup tables, for their expected range of G values, chemical sequence, flow rates, etc.

“This is a spreadsheet operators can use for quickly calculating chlorine demand of their source water – it comes in handy for jar tests and dosage changes as needed.  It requires the operator to “input”  three values and perform some chlorine residual lab tests. Try it out!”

When feeding any liquid chemical, the operator needs to check the actual output of the feed pump (in mLs/min) for a minute or two and compare that to the theoretical or calculated amount of feed rate that is intended. If the two are not the same, then the operator should make the appropriate increase or decrease as needed. This spreadsheet requires three inputs: the amount of liquid alum actually captured in two minutes; the plant instantaneous treated water flow rate in MGD; and the dosage of dry-basis alum needed in mg/L. The spreadsheet will yield the results in mg/L increase or decrease that the operator should adjust.