Doing better since the allergy meds. I was able to get out and test the pond chemistry, and we should be at a ph of 6.8 to 8.2; we’re at 8.3. A Kh (or alkalinity) of 100-200 ppm, and we’re at 80—this affects the function of bacteria who are supposed to break down waste. It’s related to ph, but is the reading you want to adjust. Our gh (general hardness) is 60, which is excellent. Our nitrate, nitrite and ammonia are all near 0, no ammonia, which is good: ammonia is lethal. And a temperature of 50: we want 60-65.
Hence the order with Amazon for 13 pounds of baking soda. 5 cups a day until we reach an optimum 150 kh reading.

I do this routinely for the marine tank. We’re getting the pond in shape. And the kh rise will help keep the algae down.
We have a pretty high evaporation rate in the summer, and I’ll be tracking the kh particularly on this set-up. We’ve also got our new winter aerator device, which a koi website does say works well.
And we’ll be looking for baby fishes soon.