Put a board to cover the front of the tank. That way, they won't be disturbed and spooked as much.
It may be quite late already since the practice of putting MB or Maroxy is usually done 45 mins. to an hour after the spawn. But since it's still in it's 12th hour, you can still try to put a wire mesh in front of the eggs. This will prevent them from eating them but still give them a chance to see them and "fan" them. The usual combination is to put MB or Maroxy to prevent a fungus outbreak on the eggs, then put the wire mesh. The mesh will prevent the fish from cleaning the eggs but the MB or Maroxy will prevent certain types of fungi, present in your water, to invade the eggs.
If you have to do a W/C, make sure the water parameters are about the same as what's in the tank.