Mine does just the opposite, it clears up considerably in the colder months, every year.
I had a lot of green oak timber and tree tops and brush piles from logging in it when it filled up, so I had a little brownish tint to it for several yrs from what I figured were tannins, but every winter it cleared up considerably.
This last summer tho the visibility stayed a lot better then before, I can see a lure or a fish at 3' pretty easily. and right now probably even further then that. I would like to get a sechi disk and see just how far I can see it but havent.
