I have received the results from the Tubidity/Nutrient tests today and I was hoping you guys could give me your opinions as to what may be going on.

Two water quality tests were taken. One about 80yds out from the fish cages and the other at the other end of the lake.
The results reported for both sites were identical;
Alkalinity 41
PO4 0.03
Ortho 0.02
Nitrate 0
Hardness 324.9

I also took a sample from a nearby lake that was similar in size that did not have a fish farm operation but would have similar runoff. The thought was to use this as a baseline and we thought we would be able to pinpoint the fish operation as the cause for the declining water clarity. Here are the results for our "control"

Alkalinity 47.9
Total PO4 0.01
Ortho P 0.01
Nitrate 0.0
Hardness 290.7

Does anyone notice any significant differences between the results or any reason why the water might have gone from "gin clear" to clarity of 2ft or less. Any outher tests that I should consider??
-Mike