pure freedom DI filter

Graeme Broome said:

Hi, I use a 200 GPD Compact Reverse Osmosis system from pure freedom. My tap water TDS reading is about 100, sometimes less, and I'm getting a reading of 0-1. I've not been using my DI filter for some time and the reading is always about 0-1. Am I okay to not use the DI filter, save me buying resin if I can live without it.

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spruce said:

My advice is to be very careful. I've just taken a measurement of the TDS of our water down to road from you and ours is 111. There have been times when our water reads 147ppm. An r/o will never be 100% efficient (0ppm). An r/o would be working at 99% efficiency with 1ppm from a tap water tds of 100. Most manufacturers don't claim that even with perfect water conditions; ie temperature, pressure and mineral concentrations.

The best I got with my r/o with an American Axeon membrane was a rejection rate of 98% when it was new. Now it's running at 97%. My pure before di has been fluctuating between 2 and 3ppm for a few weeks now.

I once experimented and found that in early morning sun I could see tiny spots on the glass from inside with 5ppm water. I doubt a customer would notice, but I can't take that chance. So I will never let my pure go above 1 before changing resin. 6 litres of resin lasts us about a year.

Is your tds meter accurate?

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