Dean,
You should be able to get away with the 3 stage - the one with the Carbon Block, the RO TFC Membrane and the DI cartridge. That should just about do it for you. The fundemental problem with these units is that each is missing one of the necessary others.
The ideal situation (IMHO) is to have a 1 micron block first - this will filter out most of the larger items, the carbon block grabs all the chemicals etc the RO TFC membrane fine tunes it to close to, if not "0" and the DI polishes it to zero if not already there.
Difference with these is that each stage takes care of the stage before it, meaning, that if you go with this 3 stage, the first is a carbon block, which doesn't take out much of the particle matter, so then it runs through the RO membrane (the most expensive of the three at $100 each) and then polishes through the DI.
I would get the three stage with 1 micron carts for the first stage, this will extend the life of your RO membrane and DI cart. BTW, the micron carts are like $5.99
As a point of reference, my unit has an RO bypass which runs the water through the micron cart, the carbon block and the RO membrane (missing the DI) and it brings my 277 tds reading down to 5
That being said, I bought a unit from
www.aquaticreefsystems.com I spend hours sometimes on the phone with them - you won't get this from a $75 unit. I paid about $220 for mine and I bought the pressure meter, the ro bypass and a TDS meter ($40 value).
So, in short, this is one of those I firmly believe you spend the extra few bucks now and get it back later. My water has NEVER been above "0" in 3 years of reefing FWIW.
House
