If you want to keep your pond fresh and clear all summer long, discover what thousands of gardeners already know???there's no better natural solution than barley straw! And our Barley Ball is the most effective and convenient way to dispense barley. Encourages clearer ponds Each ball is effective for 3 to 4 months Safe for fish, pets, plants Treats ponds from 700 to 2,244 gallons For best results, place in pond early in the season Barley Ball Refills are also available For smaller ponds (10-700 gallons), use Barley Pads Note: If you are ordering this item as a gift and it is the only item on your order, please be aware that there is a picture of the item on the outside of the delivery box Pond SizeWe recommend: 10-700 gallons1 Barley Pad 700-2,244 gallons1 Barley Ball 2,245-4,488 gallons2 Barley Balls 4,489-6,732 gallons3 Barley Balls To calculate gallons: Length (in feet) x width x average depth x 7.5 = gallons Gardener's Supply Exclusive