I agree with everything said above.
You need to shorten the height of the drainpipe and make it bigger.
Just use the next size larger pipe for the drain, shorten it, and put a ball valve on it so that you can control the drain amount (which will adjust the water level in the skimmer).
If you look at skimmers such as the AquaC EV-120, they have a large drain and use a gate valve to adjust the water level.
I did up a quick rendition of the approximate layout of how the skimmer should look. The drain tube needs to be lower than where you want the water level to be in the skimmer, that way it's the ball valve controlling the level, not the height of the drain.
This will also raise the skimmer up a bit on the tank. Rather than hanging on the tank from the top lip of the skimmer, the hanging plate will move down the body somewhat.
HTH.
DIY skimmers are fun... I built a venturi-type skimmer powered by a Mag9.5... and 45" tall.
