You have no pipes extending below the waterline and your hoses are too long. Raise them higher so trapped air can more easily be flushed out.
The water level needs to be much higher.
The water level needs to be much higher.

Need to remove the metal clamp there though if that is how you are going to run it. It is exposed to the water spray and will corrode quickly. Also you will just need to be careful to make sure that hose doesn't get tugged or pulled accidentally since it is not secured to a pipe any longer.

