We put an aerator in our pond. It took 3 years to catch up with the back log of biomass but for the last two years we have had a healthy looking (and smelling) pond with only light algae, and duckweed on the edges. Copper sulfate is one of those poisons that have to be used in just the right amounts. Too little, and nothing happens. To much and everything dies, and not enough middle ground. Biofilters are good. You don't really need peat moss for them. If the cattails are happy in your local mud, use that. The water doesn't have to circulate very fast (although it's pretty...) If you run your pond through the filter once a week, it's lots. A 1 acre pond, 8 feet deep has about 2 million gallons in it. A week has half a million seconds. 4 g/s = 240 gal/min. 240 g/min needs a 3 inch line. Also -- it doesn't need much drop. Just enough to move the water out of the way. 2 inches is enough. The lower the head, the less power you need. 240g/min = 2000 pounds per minute. Lifting that 2 inches takes 300 foot pounds per minute. Or about 1/100 HP ignoring friction. Cattails on the edge of the pond help a lot too. The wind then does your circulation. Cattails can make it a lot harder for a todler to get in the pond my mistake too, especially if you have edges that are shallow enough for a wide band of them.

A range of tools suitable to rake native plants out will be useful, before they become large clumps that seed prolific. A few burly stumps and long planks might make chasing the pesky weeds out easier and sliding a plant pot or two in position Containerising choice plants makes it easier to lift and divide plants compared to wrestling with burly plants lashed into mud Choice plants, as in they have the best choice, combination of features for that kind of large pond... slow growing, easy to control, prolific blooms, attractive foliage Planting well behaved attractive aquatic iris and hardy waterlilies suitable for a large pond would establish some choice features Phasing the bad guys (like cattails) out, and the nice stuff in shouldn't distract you much from putting feet up and browsing a good pond book or two on a nice day

I had a local rural company do it ... they do excavation and other earth-moving jobs, and are the local pond building experts. You need someone who understands what they are doing, not just someone with heavy equipment. They used a pump to pump the water out and emptied it into my back pasture which slopes away from the pond ... I had already lost most my fish from a bad winter kill because the pond had too much silt. They brought in a bulldozer and excavator and ended up right in the pond moving the gunk out. Since I was no longer using my back pasture for horses, they put the gunk in that pasture and then leveled it when they were done. If you can't do something like that, they'll have to haul it away (additional cost). My neighbors & I spend the day catching crawfish, frogs, turtles, etc. (Even the guy on the bulldozer helped) Anything we saw that we could save, we put in buckets and they ended up in other neighbors ponds. We dug it out in November, it re-filled itself (spring-fed, could see the springs bubbling up when they got to the shale bottom). The bulldozer was sparking on the rock when they reached the bottom. It re-filled itself by January. In the Spring, I re-stocked with minnows, crayfish, large mouh bass ... bluegills and frogs came back on their own, and I eventually put in grass carp, goldfish and koi. I'll post some pictures when I get home. Best thing I ever did. I read through th 70 page catalog on Zetts website, and guess maybe my pond is OK. He says a clear pond is a sterile pond. My fish all look healthy, plenty of little ones swimming around the edges and shallows. He says Koi are good to have, since they eat algae, and mine have doubled in size in a year. Might restock some more crayfish next Spring and talk to the guy at my local fish farm. But for now, I'll stop worrying about it.

check the uv is working, the tube may be out of date and not clumping the algea, uv tubes should be replace after a years running, so you get two summers per tube three at the most before they are inafective, but its not likely to be the fish sending the water green, happens to a lot of ponds at this time of year, some clear by themselve when the plants begin to kick in and create a ballance, but a new uv tube will probebly work, but bare in mind it will take upto three weeks to show effect.