First, I have read all of the posts in this thread.
I do agree that RO systems waste water. I am not a big fan wasting water either. Much of the discussion about RO vs DI has to do with how much water you need, what your source water is like, and how often someone is willing to perform the recharges (or exchanges) on a DI.
Back a couple of years ago, I was doing tons of research for my propagation facility. Anthony was someone I pestered frequently for info/advice. (I still pester him, just not frequently anymore
) While investigating DI units, I had the opportunity to email back and forth several times with Aquatechnics. I wrote to them in English and they wrote back to me in German- which I translated using LEO (online translator). I had to go word by word. I didn't know of a 'plug in a whole page' translator.
http://www.leo.org/leo_home_en.html
I was able to find three US sources for Aquatechinics deionizers. One was Dr.s Foster and Smith.
http://www.drsfostersmith.com/produ...0000&R=12993&ref=3167&subref=AC&N=2004+113073
I ended up purchasing the kati ani unit from them. Apparently, they are not handling the Aquatechnic line anymore. (???) The page is still up on their website. Probably for the same reason Anthony suggested to me that it wouldn't be worth it for me to buy the unit direct from Aquatechnic due to import taxes/customs duties plus negotiating warranty service is a nightmare. Aquatechnics has good warranty service, it is the going back and forth through customs that is the nightmare. If no other option was available at the time, I guess I would have bought it direct.
The second US source was Aquadirect, but they did not have the size I was looking for, but did sell the german kati-ani series 1 (1,100 gallons), kati-ani series 2 (2,300 gallons) and an ani (no kati listed) series 5. I have the kati ani series 10.
http://www.aqualink.com/direct/purify/deionize.html
The third US source was someone Anthony had mentioned in one of our personal communications, so I am not comfortable with giving their names, nor do I know if they are comfortable with having their names being mentioned.
The Aquadirect link is from my favorites and is probably three years old by now. I don't know if they still sell them, but the page is still up online.
As stated, I am not a big fan of wasting water either, but sometimes you gotta do watcha gotta do. My source water runs about 680 - 780 ppm TDS. It is full of iron (++), calcium (++), and magnesium (++) - all of which deplete DI resins faster than something like sodium (+). The Aquatechnics seies 10 is advertised to process 9,800 gallons between recharges. The system is two acrylic towers about 31" tall and about 27" full of resins. I got less than 350 gallons before the kati resin showed full color change and was exhausted. In a propagation facility expected to use 1,000 - 1,300 gallons each week, I would have been recharging the DI near daily. I felt (and still feel) that RO in front of the DI was a necessary evil (for me). Even after putting in the RO system, I lost 4 membranes due to the extreme amount of iron in the water. In addition to the RODI, I have had to install an aspiration/oxidizing iron removal system because a household type water softener was not adequate. The water coming out of the RO is around 8 - 9 ppm TDS and then goes to the DI. Even with all of that, I only get about 4,800 gallons or about 1/2 of the advertised amount. In this case, a DI alone was simply not a viable alternative. I knew my source water was crappy, but was convinced that a DI of that size and quality would produce much more quality water than 350 gallons.
In comparison, a series 1 (advertised for 1,100 gallons) would give me roughly 40 gallons. If you have really crappy source water like mine, be prepared to recharge those DI resins frequently.
Speaking of rechrging, muriatic acid can usually be found at any hardware store/ home improvement store/ pool supply house for about $3 per gallon. It takes about 1 1/2 gallons to recharge my series 10.
Sodium hydroxide can be found in the link below or drain cleaners (diluted). It takes 800 grams of sodium hydroxide to recharge my series 10.
http://www.chemistrystore.com/Sodium_Hydroxide.htm
Not trying to make any points of discussion, just wanted to share my experience (and the links).
