we are not living on our land yet and collect gray (dish) water in buckets for our nascent veggie garden and potted tree collection (to go into swale mounds later) anyway, i scored a hot tub/pool filter from a friend, basically a big bucket with a threaded fitting in the bottom. i think its actually a sand filter, but i just dug my own sand from the beach and put gravel on top. oh, i stuffed some old pantyhose into the back of the valve i fitted into the bottom. the flow is all gravity driven. during the rainy season i ran excess shed roof water which flushed it out, but now i'm running the dish water through it. pH tests indicate normal levels for plants 6.5 ish and so far so good. i don't want to do this indefinitely of course, but for now its a surviving solution. i think just having a container with a bottom drain is enough to get most of the detergent, which i assume floats on top (with any grease) and adheres to the gravel sand on top rather than flowing through. also we're using the brand seventh generation dish soap which i guess is more eco friendly than most. i think i just need to get the greywater oasis book and set up a proper living filter. but in the meantime, we're keeping our plants green and growing and always keeping an eye out for rain. why are we using the sand filter? good question, and i'm not sure its even necessary. it slightly clarifies the water but does not deodorize it. the big stuff we could get with a sieve/net and the little stuff is likely plant food/micro kitchen waste...i don't know, i guess its mostly to get the separation of floaties (fats and soaps) but also to feel better about giving the plants cleaner water. just a bit on our situation.