When Los Angeles County Department of Public Works inherited Lake from L. A. County Parks & Recreation, they were left to contend with a 2 acre lake with an average depth of 3.5 feet, that had been ineffectively converted from a retention basin to an artificial lake, complete with Bass, Trout, Catfish and migratory birds.
The summer water temperatures reach 98.6 degrees F, and there was little or no circulation, despite the aerators.
Algae and weeds developed, and ammonia toxicity led to fish kills. Copper sulfate was tried to kill weeds and algae, but it was not really effective, since the dead algae just added to the nutrient load, feeding the next batch of algae, as soon as the copper dropped into the sludge at the bottom. Copper sulfate also did nothing to curtail the rising ammonia levels.
Since our systems were utilized in 2001, problem was solved, water became crystal clear.