How to lower hardness?

Question

How do I lower the hardness in my 29 gallon fish tank?

Answer 1

lower hmm idk but sifen it out !with a21o plug !

Answer 2

I believe there is a type of fresh water 'aquarium salt' you can use in small amounts to soften the water.  Approx 1 tbs per 20 gallons I think is the dosage.  However if your fish are already used to that water, you  shouldn't have to worry about it too much.