For those of you that have private lakes, is there a way to keep the water very clear without investing thousands in a gigantic filter system?
In Alabama, not really. Red clay mud is so fine it really can't be filtered out without an inordinate amount of maintenance. A lot of mud-bottom ponders use cyclonic separators in attempts to reduce the amount of silt from their ponds. But, it's a losing battle since more of the bottom roils up naturally and from fish grazing and nesting. And, just feeding the fish adds to the clouding. Just check the ash content in prepared foods. Most are around 10%. This ash is usually inert binders and/or clay so, this inert material just adds to the silt in the pond. I keep the silt down a bit with lots of water plants but, it never gets rid of all of it.