Conditions tap water making it suitable for fish. Fresh Start makes tap water safe by eliminating toxic chlorine and breaks the chloramine bond. Adds Aloe Vera a "liquid bandage" to protect delicate fish membranes from raw tap water. Removes toxic metals. For each dose 25ml treats 227.3 litres (50 gals) - easy dose bottle. Treats 2,274 litres (500 gals) Vol: 250ml Suitable for use in all ponds Safe for use with all species of pond fish Harmless to filters and all species of pond fish, plants and water using wildlife