[quote=canyoncreek]somehow the forum has a glitch yesterday and today as attached files are not allowing me to open them and view them.

How does your pond hold water in the summer? IS there quite a bit of water fluctuation? Do you have groundwater coming in to replace water during the non-spring months?
We have a fair amount of iron in our ground water and iron sediment makes our leaves and dirt carry a rust/brown color as the iron settles out. It hurts nothing, the fish don't mind.

There are those who have had some success with adding healthy bacteria and muck dissolving pellets. I have not tried that. I'm not sure how much that adds beyond the aeration you are doing, but some say getting muck dissolving pellets right down into the sediment on the bottom helps to some degree.

If your pond is 25 years old then you probably just have too much accumulated phosphorous and nitrogen packed in the sediment on the bottom. Ideally you would muck out with long reach excavator, but you may not get to the bottom at 20' deep. Access and cost usually is an issue too.

What type of aeration set up do you have? Maybe you can see some gains there?

The pond fills in the spring from snow melt and spring rain and drops several feet thru summer. That is its cycle. Their is no ground feed.
Excavating would be very difficult. I do have leaves, but I rake many times and keep out most. My aeration is a buried 3/8 air line from an air compressor in my pole barn. The line comes out next to the pond and I use different things for airation. Right now I have the air line connected to a soaker hose. I think it needs improvement.