Hi Shauna;
two quick responses: Firstly, they're probably not a problem at all. Secondly, what type of grey water system are you using?
If conventional surfactants and all the other stuff crammed into cleaners isn't a problem for a conventional grey water filter - I don't see how soap nuts would cause problems. Enlighten me if I'm missing something here - but conventional grey water us pretty gungy stuff; I'd go for the natural alternative any day if I was a filter
