Bosch dishwasher?

It takes in some water but only enough so I can just see the water level above the filter. I'm sure it used to get quite a lot in the base (about 5-6 cm. deep) The arms don't spin around but water pours out of the holes in them. Have cleaned arms etc so I don't think that's the problem. Someone suggested putting extra water in during the cycle so tried that, I put in several jug fulls and all works fine?!?! Why does it not take in more water?