I've been using TSP (Tri Sodium Phosphate) for many years. I was worried when they took phosphates off the market that I'd never be able to make a good batch of anodizing solution again...not so. The new stuff works just as good as the old. I buy mine at the local hardware store....it's in the painting section, and is used a a wall cleaner prior to priming/painting. It comes in a granular form.
I mix a saturated solution of TSP to distilled water. (fill my anodizing container with distilled water, and then stir in the TSP until I won't dissolve any more.)
I've also used straight Coca-cola, and saturated salt solution with equal success to the TSP. I've come to realize that its not so much about your anodizing solution as it is the power source you utilize.