My overflow drain has gas

[outtafocus]

I have a long length of the air line tubing which came with my mj1200 (the cool black stuff). The air line drops inside the standpipe to about an inch or two below the water inlet holes.
I tried to run it with no tubing and it was horribly loud, constant air sucking sound. Then I tried just a 1" piece of tubing, and it was quieter but the water level jumped like a pogo stick.
I guess I could drill out the hole and glue in a long piece of rigid pipe, but that could be loud to.