Sneak a bag of lime in there at night, maybe some fertilizer. Seriously though I have fished some waters like that, Northern Maine has water clarity in some lakes you can see 15 feet down. I used to fish Lake Simcoe in Ontario thru the ice and we used chartreuse jigs, all you had to do was stare down the hole in the ice and when the jig disappeared you had a bite. This was in 12 feet of water. How they could keep a pond that clear is beyond me, must not be any geese around.