Control green or brown water in your reef, nano, or seahorse aquarium_x000D_ use dr.Tim's re-fresh in your reef, nano, or seahorse aquarium to control brown or green water issues. Re-fresh is a potent combination of beneficial bacteria that work together to maintain clear water, clean aquarium surfaces and eliminate unpleasant odors. Keeps surfaces clean_x000D_ maintains water clarity_x000D_ choose the size best suited for your system:_x000D_ 4oz bottle treats 240 gallons (908 liters)_x000D_ 8 oz bottle treats 480 gallons (1,817 liters)_x000D_ 16 oz bottle treats 960 gallons (3,634 liters)_x00