It looks like your RODI unit was upgraded from a 4 stage to a 6 stage.
Move the TDS “in” meter to the red line of the first DI canisters and the TDS “out” to the blue line of the final DI canister. Usually the canisters go from left to right but the “final” DI canister is the left one in your case.
I’d swap the DI canister lines to go from left to right so as not get confused in the future. This is assuming that both DI canisters are mixed resin. This was how my 5 stage dual TDS meter was setup. The “out” should read 0.
Looking at your photo you already have one side of the meter, the blue “out” meter, to the “in” of your DI canisters. Can’t see where the other meter is connected to.
“HM Digital Inline Dual TDS Meter - Instantly know the purity of your water, before and after the deionization stage. The inline probes come pre-installed and with the simple push of a button, your waters TDS is displayed on the LDC monitor.”
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