Tetra Pond Anti-Algae Block is a form of highly effective algaecide. These time-released, slowly dissolving anti-algae blocks clear pond water and help remove slime from sides and bottom. Use 1 Pond Anti-Algae Block per 250 gallons. Not recommended for use with plants.
Directions: Use 1 block for water volumes between 100 and 250 gallons (380L-950L). Initial dose may require 1 black for each 100 gallons. For regular maintenance, replace block when fully dissolved (usually after 30 days). Not recommended for use with live plants.