I thought that because they were tropical slightly more acidic is better. However, someone with more experience would have more knowledge and be able to confirm or dismiss what I know. As gbose said, CONSISTENCY is the key. Even though my water comes out acidic as can be, I would rather keep it that way than try to change it every time I have to do a water change (which is very frequent). My fish are doing fine in it.
yes, you are right. the ph test shows a tiny color change sometimes. i can never figure out why because i have a line drawn on my containers to make sure i add the same tap and the same filtered each time.
our tap water is over what my ph test card even shows. so i know it's higher than 7.8.
i will consider transitioning him to a higher ph so i can eventually use tap only.