I was always told that it's not that amount of airbubles in the water that provides oxygen to the tank, it's the amount of surface movement of the water.
If the pump is too strong and your fish can't swim with the current then turn it down (if you can) or buy a spray bar so that the surface water moves sufficiently to oxygenate the water.
You could just experiment with the strength of the current, turn it right down and if the fish starts to hang about at the top of the water gasping then there is not enough oxygen and you know the answer to your question.
Your aquarium is very bright. but I kinda like it!!!!!
Can I ask why you have such a bright background? Do you not think it detracts from the fish you have in the tank?