I think what most people would really be curious about is the salt levels. Just saying the word salt probably makes most people think of the salt on the road during a winter storm or ocean water. The salt levels I use as per instructions on the aquarium salt container's label are quite low.
I thought I was the only one who had never heard about salt in one's pond back when my fish were sick. It's on the shelf at pond stores, walmart and online. I ran into a pond person just after I had started using salt and he knew about the lack of salt making fish sick, knew what the malady was called and made me think I was the only one who had never heard about it.
You can't use just any salt, it needs to be aquarium salt to be sure it's the right kind. My pond is small, about 250 gallons and has a separate 100 gallon tank full of pond plants, primarily papyrus or umbrella plants but also elephant ears, lilies and cattails. I use a small pond pump from the pond to the plant tank with a simple media filter. Oh, since raccoons feast on pond fish, I buy goldfish and not koi.
