Lowest pond alkalinity I have encountered is 4. Never seen a 0. You can get an inexpensive test kit from Hatch or others. Test the well water separately as that could be an issue as it can have low to 0 alkalinity.
If your alkalinity is below 20 you need to add ag lime. If it is really below 5 then you need 5 tons of ag lime per acre. Might be good to get a water and soil test to be sure.