The same time I was learning how to make laundry detergent, I found this tutorial on how to make dish detergent. Since it had mostly the same supplies as the laundry detergent, and I already had all of that, I decided to give it a try. I really hate buying dish detergent even more than buying laundry detergent. It always seems so expensive, and it never seems to last as long as I think it should.
For this you need 1 cup Borax, 1 cup Super Washing Soda, 1/4 cup salt, and 2 packets of Unsweetened Lemonade Packets. Be careful, because I've read that other flavors of Kool-Aid will stain your dishwasher. Only use lemon!
Just throw it all in a container (I used one with a spout so I could pour it like the regular dish detergent boxes) and shake it up. It's really that easy...
And use 2 Tbsp per load.
...And find/make a label if you want to beautify your detergent, because that really is necessary :)
I used the same label that I tweaked for my laundry detergent; I just tweaked it a little more...
This was less than five minutes to make. It is so easy and so cheap!!
I've found that you probably want to use vinegar as a rinse aid to keep film off of your dishes (it sounds like that may be an issue with this detergent...but I've been having that problem with any detergent I've used lately anyway). I've read that you can also try to use a little less detergent (1 to 1 1/2 Tbsp instead of 2 Tbsp) or put a few drops of liquid dish soap in the box with the dry detergent.