Wow! I was simply researching how to rid the weeds around my pond and came upon this thread. Interesting conversation and amusing! However, I didn't really come away with a clear answer to my question, lol. I don't use salt much as far as cooking with or ingesting it so I don't even have a cup of salt in the house and the only vinegar I have is cider so I don't believe I will be trying out a home recipe. I do, however have Roundup. It sounds like I can use that lightly and carefully. I really love my fish and I'm nervous about harming them. I even have a baby Koi this year after having two Koi for 7 years. I assumed they were the same sex. Although, judging by the size of the baby, he had to have been around last summer in hiding.