It is not debris from a gravel vac. I have a 30" deep tank and I get the cloudiness whether I do a gravel vac or not. And it is not stirred up sentiment because the water flow is defused at the surface when I pump in the water.
We have some nasty stuff in the main river where our public water is drawn. Along the 110 mile length of the river there are 82 waste treatment plants. We have runoff from coal mines, farms, lawns (fertilizer, weed & insect killer), road salt in the winter, and a bunch of factories pumping waste into the river.
PH is alkaline during the cold months and acidic during the warm months when they pump acidic coal mine water to increase the water flow for the nuclear power station.
Mineral content also varies. The coal mine water is loaded with heavy metals.
I just read an article today that says they found trace amounts of drugs in fish caught in five major cities (Philly being one of the five). Here is an excerpt:
"Fish caught near wastewater treatment plants serving five major U.S. cities had residues of pharmaceuticals in them, including medicines used to treat high cholesterol, allergies, high blood pressure, bipolar disorder and depression, researchers reported Wednesday."
So I'm pretty confident that the cloudiness has something to do with my water.