I think you're on the right track. I wish we knew exactly what's in that stuff. Once you establish stabile parameters you may want to begin experimenting with your own recipe.
I don't know how ABN's and Rams will be affected by your new water but I don't think it will be harmful. I keep an ABN in discus breeder tanks sometimes. I use RO to bring TDS to 80 for spawning then immediately switch to straight tap water with a TDS of around 400 and they do fine with the changes. I haven't bred Rams yet but the spawning conditions are similar to discus.