You don't need both Hydro Pump and Surf. You should probably stick to Surf for reliability.
Hyper Beam is also unreliable in that the charge time will almost ensure a Milotic counter to come and take it out. Replace it with Ice Beam.
The standard Milotic movesets tend to be something like:
Surf
Ice Beam
Hypnosis/Mirror Coat
Recover
Aside from that, there's also those who use Sleep Talk and Rest over the last 2 moves to take advantage of Marvel Scale (when Milotic is inflicted with a status ailment, its Def. increases by 50%). Go with what suits your team and general battle style most.