The video does a great job explaining the difference between concentrated and non-concentrated detergents.
However, another option also exists. You can actually buy concentrated detergent inside a dissolvable gel pouch.
You simply drop a soap pack into your detergent tank and let it dissolve for a couple minutes. If you don't have a built-on deterent tank, you can simply drop one into a bucket of water.
Mix one soap pack per quart. Basically, you use 4 soap packs to make a gallon of detergent.
Since they're concentrated, they're extremely lightweight and costs much less to ship than a heavy gallon of water.