Use collected rain water.

I thought of that, but I measured the acidty ands its only like 6.8. Thats probably not enough?

Rain water works fine for mine.....I think it will work for yours as well.

Add a teaspoon of white vinegar to a gallon of water when you water the miracle fruit plants. Do it at every watering. It works great for all my acid loving plants as the vinegar lowers the ph of the water. Since the effect of the vinegar is not permanent, it would be a good idea to use it at every watering.

For other acid loving, sensitive (salt sensitive, I guess) plants, like gardenia, I use rainwater or the water produced by the air conditioner plus an acid fertilizer When rainwater and air conditioner water are unavailable (I live in the frozen North) I use distilled water which works well. These plants use less water in the Winter so it isn't too bad. About a month ago I sprinkled a pinch, literally, of garden sulfur over the Miracle Berry's pot and it put out a few leaves but I plan to be extremely careful with this and wait a month or two between doses. I think it would be very easy to over do it.
Cath

It's probably the alkalinity that affects them rather than strictly pH. Rainwater has very little alkalinity compared to tap water. But if you're inclined to be a pH nazi you can buy some pH down at the local aquarium or hydroponic store. Much stronger than vinegar.

Thanks a lot for the suggestions everyone. Pepperrot, Yeah wow, I never thought of it that way. So as long as the water is somewhat acidic, it will be fine?