About to buy a RO-DI.

AZDesertRat · Jan 7, 2014

That is the system I own myself, I have been using it for just under 6 years now and its been fantastic.
I have a water softener but my TDS is still around 550, the RO only TDS is between 2 and 3 always and thats on the original membrane. The MaxCap DI (normal versions not the 30% larger Super versions)lasts well over a year (1100+ gallons) and the SilicaBuster goes 3 years #000+ gallons). They way Spectrapure is able to do this is they use stored DI water to flush the membrane instead of tap water like others do. Also when the system shuts off it does a double flush then pickles or stores the membrane in DI water so TDS creep is not an issue.

This system is not inexpensive to purchase but I have documented it paid for itself in the first three years of use and pays me now. The sediment and carbon block filters also last much longer since you have much less water passing through them at 1:1 versus 4:1 two fifths as much?

AZDesertRat · Jan 7, 2014

Only use the 2:1 waste ratio system if you have softened water and lower than normal TDS. If you are using hard water and have normal or higher TDS keep the waste up. I believe they include a handness test kit so you can determine the hardness before trimming the restrictor.

powdermonkey · Jan 7, 2014

Thanks for the explanation! I do have a water softener. The TDS in is 500+. I am lucky to get 6 months out of the current filters

Justin_92_92 · Jan 8, 2014

Cool, Lots of great info here guys, Thanks!

Looks like the storm in central NY is going to hold up my delivery. Supposed to get it thursday but UPS was kind enough to tell me they now have no clue when i will get it

I have no clue what my TDS is currently. I have hard water and smelly water at that. (should have listened a year ago when i read about RO-DI) I have nothing thats not doing well but algae is **** tough to keep up with.

Lots of water changes in my future with a ton of cleaning i guess.

powdermonkey · Jan 8, 2014

Justin_92_92 said:
Cool, Lots of great info here guys, Thanks!

Looks like the storm in central NY is going to hold up my delivery. Supposed to get it thursday but UPS was kind enough to tell me they now have no clue when i will get it

I have no clue what my TDS is currently. I have hard water and smelly water at that. (should have listened a year ago when i read about RO-DI) I have nothing thats not doing well but algae is **** tough to keep up with.

Did your unit come with a TDS meter? If not you can buy them separately for around $30, I think. I have one on my IN and one in between the RO and DI.
Maybe the DesertRat can help here. Is the difference in quality the unit or filters? Maybe just upgrade your filters when its time.

AZDesertRat · Jan 8, 2014

If you don't have a TDS meter I highly recommend a good handheld meter over the inline types. Much more accurate since they are truly temperature compensated and they can be used anywhere, not just two dedicated spots. To troubleshoot a RO/DI you need three TDS readings so you are stuck with the inline which only reads two plus it cannot be used portable like the handheld. I also like to monitor my ATO storage and the occasional bottled water and the inline can't do that.

If you have an inline the probes should be on the RO only and the final efluent or RO/DI not the tap water. You need to know if the membrane and the DI are working and thats the only way.