If you have a decent soil, then just adjust the PH of everything she is fed to 6.5 and don't worry about it. My guess is that you are not testing the soil PH properly.
Letting water sit out a day or two removes chlorine. Brita and Pur filters do as well (ones that attach to a faucet are simple). NOt sure about chloramine.
Once I got my grow stable and my confidence up, I started simplifying to remove cost and effort. Going from filtered water to tap ( it does sit out) was one and I have seen no difference. Of course I use chemical nutes so the bennies not a big deal. So to make this clearer for the OP (and I am still not sure tap would kill them anyway), it depends on what nute you plan to use once teh stuff in the FFOF is used up.
I can say with 100% honesty that when I gave FFOF a try at a friend's insistence, my tap water that sits out did fine.