Did the coop take a soil/water sample for alkalinity? If not, I would say to take a water and soil sample and send to the extension service to get your water analyzed. You could bring a sample to Slades fish hatchery and they'll do a simple test for alkalinity.

This past spring, EWEST of this forum suggested I buy and spread 500 lbs of pelletized lime in my 1 acre pond as a "stop-gap" measure because I couldn't get ag-lime because of the wet weather we were experiencing. My pond alkalinity was measured as very low, something in the 7-9 ppm range. Note that this wasn't enough and I later had the ag-lime truck bring in 3-4 tons of ag-lime in June.

Pelletized lime is actually made from ag-lime formed into pellets and, IIRC, has a higher content of calcium carbonate (the stuff that raises alkalinity) than that of ag-lime which is a good thing as it means you should need a little less. However, here in southern Mississippi it is normally suggested, in lieu of a pond soil survey, that you'd need about 3 tons of ag-lime per acre every 3-4 years so you'll need about 3/4tons(1500 lbs) of ag-lime if it hasn't been limed in the last 3-4 years. This calculates to me that you'd need about 1400 lbs or so of pelletized lime total. Thats alot of bags of pelletized lime!

1 ac pond LMB, BG, RES, CC