I was recently at my local lfs store and they had some ro and rodi units for sale and seeing how I always bought ro water from them which was costing me more than owning my own system in the long run I decided to buy my own. Now here is the issue do I get an ro or ro/di system, the person who was working suggested an ro system not an rodi system. This puzzled me considering everyone seems to have an ro/di system not an ro system, so why was I recommended a normal ro system not the rodi system? Can someone tell me what the main difference is and whether I should get an ro or ro/di system? What system should I also get, they have spectrapure systems are those any good?