Answer: There are certain levels of e-coli that are acceptable in a normal pond. First, you want to find out what level of e-coli in a pond is considered hazardous for humans or pets. Generally, from state to state, these measurements are slightly different. But the national health organization has a standardized level of e-coli that’s considered healthy or not healthy. Once you establish that you’ve exceeded that threshold, then you move to treatment. Treatment long term can be through aeration units, such as an air diffuser. But you need to have an immediate short-term solution. We have found that the best possible solution is using a product called Pak-27. Pak-27 is a peroxide-based algaecide/bactericide that, applied at the right level, has been very effective to knock out e-coli within 24 hours.