Affordable RO/DI in Canada?

[Myka]

Originally Posted by SoloSK71

Calgary City, but where I am is at the intersection of the Bearspaw and Glenmore supply sections, on the north edge of downtown, and we get around 150 to 370 depending on season and demand.

Charles

Unless there is something really yucky in your water, you don't need 7 stages to deal with 370 ppm TDS. If you had 800-1200 ppm TDS well water, then sure. First, do you have a whole-house water softener? If so, is that TDS reading before or after the softener?

Either way, use 1 micron or smaller sediment and carbon pre-filters, the smaller pore-size helps to protect your RO membrane for longer life. The pre-filters will clog faster, but they are much cheaper to replace. Then be sure to buy an RO membrane that is 98% rejection (most 75 GPD and 150 GPD will be 98%), don't buy the 100 GPD ones, they are 92% rejection. So that will make your 370 ppm tap water into 6-8 ppm RO water. If you want to get fancy, use a second RO membrane to get it down to "almost zero". An RO membrane won't give you 0 ppm because there are somethings that will go through it such as ammonia (from chloramines). Then the DI resin will drop the 6-8 ppm (or less if you use dual membranes) down to 0 ppm TDS. Make sure you replace the DI resin as soon as it gets to 1 ppm because when DI resin is "full" it loses it's charge and will "dump" everything back out into the water. At 6-8 ppm TDS you will go through DI resin faster than someone with lower TDS, depending how many gallons you're making in a year you may replace the DI resin 1-4 times per year.

So in all reality you don't need anything more than a 4-stage, but you could go 5-stage with dual membranes. Or you could get even fancier and buy a 6-stages with dual membranes and dual DI resin. I don't see the need for this though. Depending what is actually in your water, it may be cheaper to use dual membranes in the long run OR it may be cheaper to use dual DI resin blocks. It's tough to say without a water analysis.

If it was me, I'd just start with a 4-stage and see how it performs. If you're burning through DI fast, then maybe it would be wise to add on another membrane.