Water hardness in a planted tank

[Ormarr]

From what I understand, increasing or lowering GH/KH does not affect the amount of dissolved CO2 in a planted tank.  That being said, is it a bad idea to add baking soda and Epsom salt to my planted tank to increase the PH and KH slightly? 

[fischkopp]

What good and bad is very much depends on the plant. Different plants have different preferences. That being said most of the ones that are commonly cultivated in aquariums can handle a wide range of pH and GH (with very soft South American and very hard African water being the extremes on both sides). So a slight increase of GH probably wont hurt.