Here's some great info on choosing detergents that are suitable for use in Grey Water systems from the SaveWater website. So far I'm yet to find a simple, but comprehensive guide to choosing a greywater friendly brand name detergent. Every Australian site I've come across point to the Lanfax Labs website but the information there seems to be hidden amongst a lot of scientific research.

If anyone's found a user list of biodegradable and greywater friendly detergents, let me know and I'll post it on this site.