From your numbers I am assuming you are talking pH. Hardness is connected to pH, and successfully adjusting the pH usually involves dealing with softening the water too. You can read more on the connection here: http://www.tropicalfishkeeping.com/f...quarium-73276/
On the peat, this is one way of softening and lowering pH, but the peat becomes exhausted at some pint, depending upon the initial hardness level, plus it will stain the water. This is not harmful,, but not everyone likes tea-coloured water, so I just point this out.
Easier ways to deal with this are referenced in the linked article, and I'd be happy to consider them if you can tell me the hardness values of the tap water. We need GH and KH (Alkalinity), and these you can get from the water supply folks; many have a website. If you find that but can't decipher it, post the link and I'll try. Once we know the hardness values it will be easier to suggest options.
Another thing, is what fish do you intend keeping in this planted tank? Adjusting water parameters is not always easy, and some fish do have a degree of adaptability in this area.
And, welcome to Tropical Fish Keeping forum.