Keep your pond fresh and clear with the cleansing power of beneficial bacteria and enzymes. Regardless of how large your pond is (up to 225,000 gallons or 1/4 acre), the Aquasphere will clean it for a full 30 days. Easy to use, reducing excess nutrients and breaking down organic matter that clouds water. These new, improved Aquaspheres are 100% biodegradable; the cornstarch-based "plastic" orb is designed to slowly degrade and will dissolve entirely after a few seasons. Use when water temperature is 50 degrees or warmer.