You should be able to get a good wave, make sure the top is sticking out about 3/4" so it can take in air and it is all in the timing, there is exactly one right frequency and you have to take time to find it. Also be sure you don't have any big obstacles between the outlet and the far end of the tank.
Using the wavebox pump as a powerhead will cause the transformer to burn out in short order. You would need to either downgrade the propeller to 6105.700 or upgrade the transformer to 6300.240. You can basically run it as a 6105 with a larger outlet cover or fully upgrade it to a 6305, but run continuously it is a 50W pump on a 50W power supply and it won't last long, it relies on the controller cycling it so it averages 25W to make this combo work.