I have an intermediate z-spray with one 7 gal aux tank. I do not use the fert tray much, so I am thinking of getting either the extra 7 gal aux or the isolated 7 gal tank with its own pump and coil spray wand. I am in a pickle to which one to get. For guys that have the isolated tank, how is the coil spray wand and is it heavy duty? The one problem I have about having three different chemical in each tank with the standard 50 ft spray wand is that when I want to use a different chemical out of the wand, I will have to some how get rid of what is in the 50 ft hose already to get at the chemical I want to use . The isolated tank would solve this issue. Having 30 gals of regular weed control product would be great too or having 25 gals of 3-way and 7 gals of q4 plus would also be good. Any advice and opinions would be appreciated.