Formulated to remove residues caused by fresh water including scale, silicate, calcium, sludge, and all other mineral deposits. Can be used by one of two methods: Immersion: Isolate the tanks, fill the entire system and let stand. Circulation: Inject PSR into the tank, mix, run faucets for two minutes every 15 minutes until the tank is empty. Fill the system and rinse. Description: Concentrate 1 Gallon.