what species again? my guys lived at my parents house for almost 2yrs on hard as nails well water Ph 8+ KH/GH both off the charts. most the African species should do just fine in it... just like other fish I would do a slow acclimation ( ie if your using aragonite to buffer add a few cups a week until your get the substrate where you want it) I would be most worried as to what your using to buffer as crushed coral ect is very sharp and could easily scratch them up.