I have
this RO system. I've been using it about a month now. I can't answer all of your questions but I can tell you what I've done with mine.
I have a utility sink in my basement and I run my
RO down there off of that. I got a quick disconnect hose coupling to easily connect it to my faucet. I do recommend purchasing a
TDS meter also. It is the only way I know to check to make sure you
RO is actually working. The
TDS (total dissolved solids) on my
RO water range about 2-6 with my meter. I also purchased a flush valve for mine which I use for about 5 minutes every time finish using it and I've got a float kit but I haven't installed that yet. I don't have any idea how long my different cartridges will last or how I'll know when they are used up but I'm assuming my
TDS will slowly start to climb and that will be an indication that I need to change things out.
The system does generate a lot of waste water. Basically water is pressurized and forced across a membrane. Only water is supposed to pass through the membrane. The stuff dissolved in the water stays behind and flows out the waste water line. I have my waste line flowing out through a drain in our basement that daylights to a nearby field. This way it doesn't go through the septic system. In the summer when it's not freezing out, I'm hoping to collect some of the water to use for watering my plants and garden.
My well water is very hard.
GH 20 and
KH 20-23 and we have a water softener so I am running the softened water through the
RO so the
RO doesn't have to work so hard.
Aquatic Life has a web page with FAQ for
RO/
DI systems
here. It may also help to answer some of your questions. Good luck!