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Discussion Starter · #1 ·
It's about time I change my filters in my RO/DI unit and I want to make sure I get the best ones I can. AZDesertRat had a post outlining the things to look for but I can't seem to find it. Any tips on what to look for and where to get them from?
 

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There are a lot of threads he has posted in re: filters and such. Might be easier to shoot him a PM
 

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Discussion Starter · #3 ·
I spent my entire half hour lunch searching for it but couldn't find it.
 

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Low micron, absolute rated sediment filters are better than nominal rated filters. A single 0.5 or 0.6 micron 20,000 gallon carbon block is also better than two higher micron shorter lived carbons.
I buy all my filters here:
http://www.spectrapure.com/email/customer-appreciation.html
Towards the bottom of the page, the 0.5 micron sediment is $12 and the 0.5 micron carbon is $13.
The SilicaBuster DI is $18 and their new Super SilicaBuster is $22.

I have done so many threads and posts on replacement filters I am not sure which one you may be looking for but Spectrapure has an excellent write up here:
http://www.spectrapure.com/faq_p1.htm
 

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I have been looking a the stuff on spectrapure. It was the only thing I could remember you saying. I found out pretty quick that it would take forever to find the thread I was thinking of. Is the DI resin something you just pour into the canister?
 

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You can buy bulk resin or prefilled cartridges. I suggest not buying any more resin than you can use in 6 months times though as it has a shelf life and loses strength with time and improper storage. I have personally found Spectrapure resins last 3 to 8 times longer than any other I have used so one refill lasts me up to a year even in Phoenix with high TDS.
 

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You need to calculate your rejection rate to know if the membrane needs replacing.
Get your tap water TDS, RO only TDS and RO/DI TDS numbers.
To see how well the membrane is functioning the formula is:
Tap water TDS-RO only TDS/Tap water TDS x 100.
As an example, say yout tap water TDS is 100 and your RO only TDS is 5.
100-5=95, 95/100=.95, .95x100= 95% rejection rate or removal efficiency.

I try to stay around 96-98% efficiency so DI resins last longer and I get 0 TDS RO/DI water. When the membrane efficiency starts dropping off the DI needs replacing much more often driving the cost of ownership up dramatically. For every 2% you drop, you cut your DI life in half. A new Spectrapure membrane and matched flow restrictor is like $40-$45 and it does not take many DI replacements to pay for a new more efficient membrane.
 
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