BioGuard SoftSwim A is an algaecide. Using an effective algaecide is a critical first step in the SoftSwim program. This product protects against a broad spectrum of algae. It is formulated to remain stable against the UV rays of the sun and against high temperatures. The SoftSwim program is ideal for in-ground or above-ground pools containing less than 25,000 gallons of water, pools that have bottom drains, and pools that have excellent circulation with the pump operating at least 12 hours per day. SoftSwim A sanitizes with biguanide.