no run to waste is easy, fresh water, fresh nutes, its the recirculating systems that suffer. I use Hydro Organics mate, what else. I use a soil filter, so i maintain high levels of soil microbes even in my water tanks, this helps reduce the problems relating to recirculation. Effectively the system runs through a soil filter system which acts like a strainer, the water picks up unused ion and polutant organics, Hetrotrophs like Bacillus Subtillus and other useful bacteria chealte micros and store NPK preventing organic matter spoiling the system, and so preventing my Fe acid climb and related cation lock out.
see here
http://organicsoiltechnology.com/wp-content/uploads/succesful-organic-hydroponics-1.pdf