We have a water softener (using salt) which was just put in for all the taps. (We used to have hard water.) The only thing that's hard now is the well outside. i have fish that like ph of 7.2-7.6. Would this soft water have a low ph? i did a water test and it looked like it was still 7.4 ph. Is that right? Can i still use tap water for my fish?