My local LFS recommended the Spectrapure 90 gpd when I was in the market last spring, and based on the comments I'm seeing here, I'm glad they did. I do usually get < 2 TDS out of the RO filter and 0 out of the DI.
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You do not need nor want 3 filters in front of the RO membrane if you are using high quality filters. One 1 micron or less near absolute or absolute rated sediment filter and one 1, 0.6 or 0.5 micron carbon block, thats it no more and no less.
The reason many vendors still use two carbons is they use a coarse sediment filter which does little to protect the downstream carbon so the first carbon is a sacrificial filter to make up for the poor sediment filter. Doesn't matter if it is free chlorine or chloramines, one 1 micron or preferrably 0.5 micron carbon is more than sufficient for our needs. Carbon does not remove chloramines, it breaks the bond with the ammonia and removes the chlorine portion and the ammonia is partially removed by the membrane and polished off by the DI. Good DI if far more important with chloramines than carbon is.
BRS hasn't made anything. Companies like Puratek and others have made catalytic carbons for decades which is what is used in industrial applications with high chloramine or chlorine levels. The EPA limits chlorine or chloramine residual levels to 4 mg/L and most utilities use much less than that so a good single carbon block 1 micron or less has been proven to be completely effective.
http://www.reefkeeping.com/issues/2003-11/rhf/feature/index.php
http://www.reefcentral.com/forums/showthread.php?t=1735402
The BRS videos are skewed, nowhere will you find levels of chloramines they used in their testing. Good sediment filtration to protect a single good carbon block which removes the chlorine portion of chloramines, a good high rejection rate RO membrane and a full size vertical, properly packed DI using the correct, fresh resin bed with the correct contact time will get it every time.

I agree !! I tested the city water here in Nashua with TDS and it read 254. That was during the summer time. I just retested it and got 156. I don't know what these utility folks are putting in the water but I do know I want zero.You have more faith in public utilities and gov regs than I do. For the most part I agree with you but areas are absolutely going to have water that is worse than others (even if they are "minimum spec"). In my life time however, I have never seen a single example of a gov ran.....anything (or regulaulated for that matter) that didn't have failures...(its not rare to see spectacular failures).![]()
TDS is not a contaminant and us not a health risk by itself. It has no maximum contaminant level and is not regulated since it is considered an aesthetic nuisance. It is not a measurement of anything specific and only means something electrically conductive is present. It could be all calcium or magnesium which are beneficial. It is the many hundreds of substances that are regulated by the EPA and have maximum contaminant levels that are important and which your water utility must test for and report annually to their consumers that you need to worry about.

