I do appreciate the link but I did all the searches I could and read all posts before asking. The previous discussion really doesn't tell me anything about it.

I am not too concerned with tying up phosphates. The water up here is so fertile that if we ever fertilized we would have to drain the pond and start over. I think alum would also trap phosphates to a certain degree. but there is always more where they came from. I would be more concerned that trapping it on the bottom would keep it from breaking down and it would just be saved for later when the seal is broken.

Baraclear is also buffered so they say, so there are no ph concerns.

I was hoping to find someone who has actually used it. I have called the company several times to ask some questions about it but haven't talked to an actual person yet.