FREMONT, Neb. - State experts think they've found a way to knock out toxic algae and restore water quality in sandpit lakes.

Health warnings have often closed Fremont Lake No. 20 because of concerns about blue-green algae and the toxins they release.

Two years ago state experts killed the lake's population of carp and other rough fish and treated the water with aluminum sulfate and an algaecide.

Experts say aluminum sulfate bonds with phosphorus, which feeds the algae, and takes the algae to the bottom of lakes. Killing the fish removed another source of phosphorus.

Officials say the process apparently worked, because the lake wasn't closed at all last year because of health concerns about the toxins.