MP10 not pushing much water ,, options ?

[Myka]

I have a Tunze 6055 in my 50-gallon reef. It is the only pump in the tank. The 6055 is rated as pushing slightly less water than the MP-10. I don't know how that plays out in the real world because I haven't owned an MP-10 before. However, I am able to push a ton of water with the 6055 with the pump positioned high in the tank as described in my post above. If I position it lower in the tank or pointed down into the tank then the water barely moves around the tank.