I finally broke down and asked a friend here to help me select an RO system. My husband just ordered an RODI for me that has a 100 gallon output. Here's a link to the one I am getting-
http://www.aquaticreefsystems.com/Reverse_Osmosis_4Stage.htm
I believe my husband may have ordered replacment cartridges at the same time.
One comment according to the friend who helped me select this system, we don't need RODI and RO is believed to be more than adequate. My husband placed the order and I wasn't around when he did it so he went for the DI.
Comments made regarding the added benefits of the DI were as follows-
"you should probably be just fine with a standard RO, unless you are planning a tissue culture lab or surgical center then you should go with DI. I also use the 75 gpd system but will be upgrading soon to 150 gpd. You will definitely need the solid white or opaque cannisters for use outside."
This being said, I'm not planning on any surgical procedures over here other than splinter extraction with a tweezers and I had not planned on doing any more tissue culture and if I did, I could have purchased a gallon of RODI so we should have ordered the 3-stage value line system that was considerably more affordable-
http://www.aquaticreefsystems.com/discount_reverse_osmosis.htm
What do people not understand about "no tap water". Good question. What do most people not want to understand about the word "no" in general. I have an entire household over here that seems to forget the meaning of the word "no" whenever convenient to do so. It's called laziness or cheap most of the time. I had my tap water tested over here and it would have killed my plants. Some tap water is ok. Most is not. Testing water can be very expensive. My best friend is a mircro biologist. I get all of my testing for free. Does everyone have a friend who can test water for free on a whim? Probably not. That extra element of confusion that gets added to the equation, is that there really is some well water as well as city water out there that is perfectly fine to use on these plants. I have known people who have hauled in water for years only to have had their water tested to find out they could have used their tap water. Best to take that extra step and test the water or don't use tap.