On green pond I would add some ag lime with both Ca and Mg in it to get the hardness up (only shown limiting factor) and it will help with pH swings. What time of day were the tests done?
Same for 1 acre pond (no 2)
Same for pond 3.
See this re hardness/alkalinity.
https://srac.tamu.edu/index.cfm/event/getFactSheet/whichfactsheet/112/ However, where sodium
bicarbonate (NaHCO3) is responsible
for alkalinity it is possible
to have low hardness and high
alkalinity. Acidic, ground or well
water can have low or high hardness
and has little or no alkalinity.
Would also suggest you get the pond bottom soil tested.