New TDS Meter - reading of 21 from Calgary Water?

[EmilyB]

I only got a reading of 2 from the output (post DI) after six months, and there is MAJOR water consumption going on here....
(water changing tanks totalling over 350g at 20-30% every two weeks). I've read to change at 1. I wanted to check my membrane mostly, and still get 95% rejection from it, so I don't think that was the problem.

But my last DI cartridge, color changing variety, only lasted weeks. :? Very strange. So, I'm going back to the non color changing, which I had first of all.

I'm just kind of stumbling into this as well. Running my TWP again now while I wait for my DI refills.