Recently, I saw a recipe for a soap scum cleaner. I tried it one day and love it. I did make some changes, though. My spray bottle didn't like it when it was a 1:1 ratio, so I made it a 2:1 mix of vinegar to Dawn. It works awesome, it even broke up some of the mineral buildup around my bathroom faucet. I use it in the toilet, on the sinks and the bathtub.
And I used it as the starting point for a dishwasher detergent. I have found that most of the dishwasher detergents I have tried leave a powdery film or don't get my dishes clean enough, except of course the ones that are expensive. I had tried just dish soap and baking soda, but that led to some powdery residue and bubbles overflowing the dishwasher and covering my kitchen floor.
Homemade Dishwasher Detergent
One part Dawn Dish soap (the blue concentrated one)
3 parts white vinegar
I usually just eyeball it, but of course you can measure. Mix in an old dish soap bottle. Give it a good shake before each use. I use just under 1 Tablespoon per load. My dishes come out clean with no powdery residue. I also usually use plain vinegar in the rinse agent dispenser.
You may notice that the dishwasher detergent will separate sometimes, just shake it up before using.