Not kept them yet myself Gerry, but I thought modern thinking was that if you find a local breeder you are morew likely to get a match with their water and won't have to make too many adjustments.
I bought my HMA filter specifically so I can have the water how I needed it for the discus. With our water so soft as well, all I have to do is remove the heavy metals, etc rather than go RO. With that done my pH sits at around 6.