The season of toxic algae blooms is here. A helicopter crew spread copper sulfate over Lake Skinner near Temecula on Thursday, June 6, to combat a cyanobacteria bloom — also known as blue-green algae — that had been producing some cyanotoxins and unpleasant tastes and odors. The bloom doesn’t endanger water that will be delivered to customers, and swimming at the lake was already prohibited, but signs now warn visitors not to let pets drink the water or swim in the lake, to throw away fish guts and clean fillets with tap or bottled water before cooking, and not to use lake water for cooking, Metropolitan Water District spokeswoman Rebecca Kimitch said.