I have used the peat method before (breeding A. Australe). This method strongly depends on what the water from your tap is you're dealing with right now. If 'too hard' a mixture of RO will work better.
That said you then will need to ensure you have the SAME exact mixture of tap-RO EACH water exchange. Otherwise if you keep exposing your fish to swings every week that is not healthy at all.
Hey thanks for the software....here I am using just about any new googel tool released and hadn't heard of that one...my geek's must be asleep
Really...I can only encourage you go out to any pet store/ chain store today. Buy yourself a liquid test kit (such as offered by API) that incl NO2, NO3, Ammonia, pH and Hardness and TEST your water before going don the route of heavy RO set ups there. You'll need the kit anyway once you start your tank so you may as well go ahead and buy one no. And yes I know they range from $20-30 but that's WELL WORTH the cost considering the health of your fish and you'll always need it over & over again and these kits last forever & a day