GH booster: Mg – Ca buffer to increase the general hardness (dGH).
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 GH-value expresses the water content of calcium and magnesium in ºdGH. If GH is below 3ºdGH, virtually any plant species will be in lack of calcium, and a large part of the rapidly growing stem plants will already have problems with calcium deficiency if GH is lower than 8.
The ideal GH-value for a planted aquarium is 8-15ºdGH, but as mentioned, certain plant species thrive down to GH 3, and some of the fast-growing stem plants thrive well in GH 20. Note: GH increase may not always be measured immediately, since the effect may be delayed up to 2 days.
How to use: 1 ml GH booster per 5 litre water increases GH with 1ºdGH. 5ºdGH should be the maximum increase per day, as some fish species may be sensitive to major changes.