The most efficient way to use Aquascape Ecoblast is to shut off your pump, and then sprinkle Ecoblast directly on problem areas including string algae. Allow the product to sit for a few minutes, then turn the pump back on. If algae growth is excessive, it is recommended that you physically remove as much of the algae as possible before application, making the product more efficient and preventing decaying algae from disrupting your ecosystem or depleting oxygen.