I've got a new to me 6 stage brs rodi unit. Pretty sure I've got it connected correctly-not much to it. The tds meter show 0 in and 3 out?? It has the 150 GDP upgrade and output is really low-1/2 gallon in 30 min. Water pressure is a little low at 40 psi. The unit makes absolutely no noise-don't think it has any power or on off switches-is that common-any ideas/help is appreciated.