I was having a problem with my dishwasher smelling and realizing no one ever connected the air gap into the system. My plumber bailed on me today, but I've done everything (including replacing the smelly dishwasher drain line), EXCEPT getting a line from the air gap to the disposal. I've tried all lengths of 7/8" hose but no matter what, it kinks. It's a heavy thick black hose that the hardware store sells specifically for this purpose, but I cannot get it to work. Is there something I'm missing? I've angled the air gap in the best configuration that I could find to ease the hose line and I've tried to use the hose as it naturally curves, but still cannot make it work. I'll have to buy another one if it needs to be longer, but longer didn't seem to help. Is there a better type of drain line for this application? Can I put in a barbed 90 degree connector or would this cause a problem?
Dishwasher drain line is usually cheap corrugated plastic (neither heavy nor all that thick), which is mostly immune to kinking. Some models come with a large 'U' shaped bracket to help achieve this curve.
Some come with an integral 90, so I don't see why you can't use one if you have to.
I'm pretty sure if it's black and non-corrugated, you bought the wrong stuff. That sounds like an extension you might use if it's extremely far from the drain pipe. Use what came with the dishwasher to make the air-gap, and attach that line to the drain any which way you can.