During warm weather algae can collect rapidly in water tanks reducing surface area. Left unchecked it becomes a nuisance to maintenance and can even be a potential source for contamination. Controlling algae was a losing battle for Robert Pierce, M.D., from Mementau, La., who used water tanks to supply water to his small beef herd.

"Recommendations to control the algae ranged from putting goldfish in the tanks to using copper sulfate. But none of them worked for me," says Dr. Pierce a retired medical doctor. "Don't use copper sulfate because it can be toxic."

Then one day while walking by swimming pool supplies at Wal-Mart he got an idea. After checking the labels and consulting the manufacturer, Dr. Pierce began using a product called HTH Granular containing calcium hypochlorite intended for swimming pools.

"Calcium hypochlorite is quite safe for any kind of animals, but I checked with the manufacturer to be certain," says Dr. Pierce. "I sprinkle a couple of table spoons daily into my 50 gallon water tanks. It's fairly cheap and it's easy. I just keep the hard plastic container next to the tank."

"The amount you would use would depend on how big the water tanks are. According to the gallons of water being treated, you could add a dosage of granular chlorine every couple of days," responds Julie Bishop, customer care representative for ARCH Chemical company.

"Read the label to be sure the active ingredient is calcium hypochlorite as there are other products containing chlorinating compounds that might not be safe," recommends Dr. Pierce.