R/O vs DI

Is there a difference if you use straight R/O(no DI polisher)

And what is the difference in quality of water if you use straight DI vs R/O only?

Lets say that your R/O machine gets your water down to 4 or 5 ppm???

I’d say that in general you should be able to go w/out the DI if the RO is getting you down to those numbers. I think a lot has to do w/ what kind of minerals make up the 4 or 5 ppm you have left. Some minerals spot no matter what the ppm is.

I’m curious which minerals always leave spots and how do you test for them?

Thats not 100% true if you have less then 0ppm there will be no spotting what ever the minerals that are going in to your water system.

Well i am going to buy a R/O system and i heard that you might have better results without a DI polisher, is this true or just a myth?

So, Chris,Alex,Shawn Gavin. I will be giving you a call… Lowest price wins my business.

After reading my comment I see I forgot to say above zero ppm, duh.:o

you are always going to have better results with DI then RO. An RO will remove 98% of your TDS where DI will remove 100 % of your TDS it may not sound like it matters much but it will at a job that has a high TDS coming in. I would say get a DI polisher with what ever RO you buy.

Not true at all. One way or the other. There are 3 ways to “pure” R/O, DI, Distillation. As long as the TDS reading is “generally” under 10, it is going to be “spot free”, no matter how you get there.
A polisher will help ensure a “spot free” rinse. As R/O only can go up and down “slightly” but it can.
I run R/O only in an area, that averages a 650 TDS ALL day long…

All I can say to this is… I am so grateful, my clients dont share your opinion! Sometimes service, after the sale speaks VOLUMES!

So what’s the verdict then? What minerals will always spot just over 0 ppm? And can you test for them?

First off there is more then three ways to “pure” water second the 650 TDS you have in AZ means very little in other parts of the US and what happens if he buys an RO and runs in to 1400 TDS like in some parts of Texes don’t you think he should have as much info as he can get when spending so much of his hard earned money?

It was either Shawn or Bill that was talking about this scenario and I can’t remember which ones they are.

I will not argue that point Bill, However I dont know of any other processes that would be feasible for window cleaning…

Source wikipedia… Other processes are also used to purify water, including reverse osmosis, carbon filtration, microporous filtration, ultrafiltration, ultraviolet oxidation, or electrodialysis. These are used in place of, or in addition to the processes listed above.

I have sold an r/o system to a guy in Texas and he is daily getting below the 10-15 mark… Any one using over a 500 TDS source "should " be using a TDS polisher…

Good Luck…