pH OK: Bicarbonate buffer to increase the carbonate hardness (dKH).
In case your tap water is soft (<3ºdKH and<8ºdGH) or you are using RO or deionized water because your tap water is polluted, the use of pH OK and / or GH booster is recommended.
The KH-value expresses the bicarbonate content of the water (HCO3) in ºdKH. The KH-value affects the pH value (in interaction with the water content of CO2). If KH is less than 3ºdKH, there may be a risk of a sudden and violent pH crash to the detriment of both plants and fish.
The ideal KH-value for a planted aquarium is 3-10ºdKH. Reasonable growth can, however, for most species be obtained at KH 15, for some species even KH 20.
How to use: 1 ml pH OK per 5 litre water increases KH with 1ºdKH. 5ºdKH should be the maximum increase per day, as some fish species may be sensitive to major changes.