Colombo pH Min contains specially selected active substances which reduce the pH of your pond water safely and effectively. The optimal pH value for fish and koi ponds lays between 7 and 8. Test your water frequently and correct when needed. The pH value is a reference for the amount of acids dissolved in water. The pH can have a value between 0 and 14. A low pH means the water is acidic and a high pH means the water is alkaline. Large fluctuations in the pH are harmful for fish and filters. Colombo pH Min is available in the following sizes: - Colombo pH Min 1Ltr - Treats 10,000 Litres - Colombo pH Min 2.5Ltr - Treats 25,000 Litres Directions for use: Dose no more than 50ml per 1000 litres. If needed, dosage can be repeated the next day. For safe pH reduction the KH value should be at least 6°DH. Reduce the pH gradually, do not reduce with more than 1 unit per day.