Sorry my hose is 19mmThis sounds good, but could you show me a diagram please, the way i figure it is I plug my 15mm hose into any standard 10'' casing holding the prefilter which then connects to the 4040 membrane(do I carry on with 15mm all the way?) and where do i connect the ro switch and what diameter are the inlets/outlets in mm on the 4040 membrane, what will the tds reading be when it ends up in my tank, considering its 147ppm from my river,will I still have to use a di vessel? If it takes no more than 1 hour to fill my tank I will also fill up while I am working at clients. And also, why isnt everyone using this system? its seems to me the best value for money?