Just tested my tap water here in Langley. At 93 ppm right now, highest I have ever seen it. RO output water is 3 ppm and DI output is zero (as it should be), so I guess the filters are doing their job.

I think the variances are due to either construction going on nearby or they are they are cleaning/flushing the pipes. Don't know what else explains the brown sediment we see sometimes on the filters.