Here's the details, 18yr old 35ac sand pit, max depth 27', no run off enters the lake, no trees within 100 yards, normal visibility 2'+, high quality fishing the past 10yrs, no power boats-only electric motors. Surface water temp today was 65*. While fishing today I noticed bubbles coming up from 18 FOW. It looked like the bubbles were bringing up huge clouds of redish brown water. I tried to find clean water to fish but by noon the whole lake was very dirty and small bubbles were rising over most of the lake. It almost looked like a volcano was erupting under the lake. In the past when this lake turned over there were chunks of decayed matter floating around for a few days, not this year. There is another 100ac sand pit across the road, 100 yards away that is very clear, 4' of visibility. The lakes are not connected. Any idea ? Thanks.