Water treatment GH+, increases total water hardness - Aquatic science €16.00 GH+ Increases the total hardness of water. The optimal GH should be higher than the KH and generally greater than 8. Rain water reduces the value of GH and too low value damages filtration and development of flora and fauna. For this it is important to regularly check the value of the GH, especially after heavy rains or long drought periods and correct... Visualizza