Do your own piping, it's very simple. The trip is to make sure you plan it out well, purchase all the right stuff, and get stuck into it! My overflow piping took 18 metres and I have two pipes feeding into the top of the tank. At the moment though, it's full and my back yard is under 3 inches of water!!!!!
Greywater should be fed directly underground if you can. Something to do with the phosphates and scientific stuff from memory. Greywater can be stored if you run it through a catalyst setup which is a little exxy again. I was going to feed all grey water into underhouse tanks and then filter and catalyse it for garden use only. But then I realised I really quite hate gardening and couldn't be stuffed. There was also some thoughs that it shouldn't be used on edible gardens but I haven't looked into where that is of late. However, I am putting another 4000 litres worth of storage off the house in a few months time. The current tank goes straight off my shed. I have a little experience with rainwater harvesting and tanks as I worked on the team that setup the BlueScope Water tank business a couple of years ago.
