What products should i use to lower water hardness??

Question

i have just tested the water in my 90 ltr freshwater tank as it seems to have turned very cloudy very quickly. on the reading it said that the general hardness of the water is double than what it should be. what sort of products should i use to lower the general hardness. please help as it is getting to me the fact that my tank does not look as nice as it should do.

Answer 1

either add distilled water or rain water