Thanks herbalmom!
Here is my modified formula that I use now. Since I use it for scouring, washing dishes in the sink AND for the dishwasher, it comes in handy to make it in a larger quantity. I keep it in a sealable bucket inside a zippered, plastic bag.
2 cups borax
2 cups baking soda
1/2 cup salt
1 cup citric acid
30 drops lemon essential oil
We don't miss the store bought brand a bit.