Maybe the OP isn't aware of the proper PH for dats and/or discus and would like to be informed, hence the reason for the thread. If you aren't going to help then don't post...it makes you seem like an A-hole.
OP.... Datnoids thrive in a ph between 7.0 and 8.0, while Discus prefer more acidic water closer to a ph of 6. That being the case it probably isn't wise keep them together.