Yeow. Let's go through the issues 1 by 1.
An RODI system with a single membrane, single DI stage, and inline TDS meter should be configured with a THREE probe meter. You're seeing the problem with anything less right now. A 3-probe meter allows you to read your 1) incoming feed water; 2) permeate (aka RO water); and 3) DI water. The most straightforward way of doing this is with a three probe TRM1 meter
https://www.buckeyehydro.com/trm1-tri-inline-tds-meter/. Because you already have a single probe meter, you'll want to supplement that with a TWO probe DM1
https://www.buckeyehydro.com/dm1-dual-inline-tds-meter/
Your first DI cartridge was poorly packed. If I were you I'd ask your vendor for a refund. When DI cartridges are not packed tightly enough, after a bit of use you'll see an airspace at the top of the cartridge - your pic earlier in the thread shows this. When the cartridge isn't packed tightly enough, the DI resin bed will fluidize in short order, the cation and anion resin will separate; you'll no long have "mixed bed resin," and you'll see what looks like a color change
at the top part of the cartridge. Your pic earlier in the thread shows this. The treatment you'll get from the DI cart once this has happened will be degraded, even with new resin.
The damage you show inside the neck of the DI cart is irrelevant and will not affect the TDS reading coming from the DI cart. However, because I can't see a nice full circle indentation from the knife edge seal in the white gasket, I'm wondering if the DI cart wasn't centered and you had some flow bypassing the gasket. This would definitely affect the TDS in your DI water.
As noted above, your tap water contains chloramine. Your system is not configured ideally to deal with that. This situation can be addressed easily. BTW - the carbon block that you bought in the kit from
amazon is a super low-end block with very low capacity. I'd not recommend it for chlorine, let alone chloramine.
Russ
