i'm not sure about the hardness an buffering aspects, but i do know that a member here had the easybalance actually crash their cycle. for a water conditioner i'd use either prime, stress coat +, amquel +, or ammolock (ammolock changed the formula a little over a year ago so now it works the same way as the others rather than "locking" the ammonia).
how high is your ammonia? to fix that you should do daily 50% water changes until you get your tanks cycle back under control.
have you tested your pH from your tap? do you have any
driftwood in the tank? you can use crushed coral or limestone as a substrate to help raise the pH naturally, using chemicals to change it can be very stressful on your fish, a stable pH is better than one that fluctuates.