Control Green or Brown Water in your Saltwater Aquarium Keeps surfaces clean Maintains water clarity Dr.Tim's Re-Fresh is a potent combination of beneficial bacteria that work together to maintain clear water, clean aquarium surfaces and eliminate unpleasant odors. Re-Fresh revitalizes green or brown aquarium water and keeps your water crystal clear! Because the condition of every aquarium varies, it may be necessary to add Re-Fresh more frequently (every other day) to achieve desired results. Directions: Shake well before using. Dosage: Add 5 ml per 10 gallons of aquarium water. Re-Fresh should be added on a weekly basis to help maintain a clear, clean and sparkling aquarium. Caution: Re-Fresh may be harmful to snails and shrimp. Do not overdose on tanks containing these organisms. Wait 5 to 7 days after final dosing to add these organisms. Choose the size best suited for your system: 4oz bottle treats 240 gallons (908 liters) 8 oz bottle treats 480 gallons (1,817 liters) 16 oz bottle treats 960 gallons (3,634 liters)