Hmm that’s interesting. So basically not wasting any water with the waste line and not having to worry about remineralization. I would just double check the chlorine levels in the waste water. Should be clear but just to be safe. What’s your TDS out of the tap?
Just started running RO DI still doing first 2 hours of break in but its ready a TDS of 92-93
If you just run it through the sediment filters, carbon blocks, and chloramine filter it wouldn’t. My only concern would be pressure since without the RO membrane there wouldn’t be a lot of restriction. How’s your house water pressure? I can’t remember how much psi these units can handle. I run my unit between 85-90 psi without issue with the full RODI (no chloramine unit). The BRS 5 stage units come with a built in pressure gauge. Or you could make your own by hooking up RODI canisters and customizing them with however many sediment and carbon blocks, plus the chloramine remover.
My current pressure is 55 psi. I think a booster pump may help but I dont want it if its going to be loud while on or cause a weird vibraton / resonance through the home pipes. I think 55 PSI is borderline good. Just dont want to add another layer of complexity that is loud.