It seems like the ph is the only problem with using the soft water. In my 100 I have cichlids and cat fish, that is the only tank that is low on the ph, Ican't get that tank up on the ph. All the others is also around 8 on the ph but the fish seem to be doing fine. I have had my tanks up and running for about 6 months now and i haven't lost any fish due to ph. I am just guessing as I go along. I read alot of what everyone else is doing and come up with my own thing to do and try, so far so good. I guess the fish adapt to their enviroment. They seem to like it, they are growning and reproducing just fine! 
