I have about 1/3 acre pond about 6' deep stocked with rainbow trout. Before I bought the property the water was clear but all summer now has been very murky. The pond is cold water and fed by two natural springs. One flows down a small stream into my feeder pond, the other is tapped and has an underground pipe running directly into the pond. I cleaned out most of the feeder pond earlier this year and got the pipe flowing again but the water in the pond is still a murky green/brown even though the feeder pond is now clear. The pond has a natural clay bottom. I've been doing some research on the net through newsgroups and different bulletin boards and am getting a LOT of different views. One local farmer around here says he'll give me some fresh water mussels from his pond and they act as filters. The research I did on mussels says that during their larval stage they are a parasite to fish but are generally harmless. But it doesn't tell me what fish they are harmless to and they need specific types of fish to propagate but they don't say which kinds or which kinds of mussels I should actually use. Some of the other advise I've gotten is; to use gypsum on the water, to try adding alum to the water, add some grass carp to eat up all the algae, use chemicals from a pond store on the water. Before I go any further I was wondering if you had any advise or outlooks that might help with this problem? Although the mussels seem the most organic treatment I'm hesitant to introduce any new species into the pond especially as they could end up going down stream into other waterways as well. Thanks.