RODI unit

[Microscopic]

Hi everyone,
Getting back in the hobby. Saltwater, fish only. 29G.
I am looking to get an RODI unit (did not use one on the first go round). It will be a simple set up at the basement utility sink. Cost is a consideration of course, but more so the long term cost (unit plus filters over time) rather than initial set up only. I do not need a high GPD. I would prefer a unit with a low waste water ratio and, when possible, I prefer to shop local.
My questions are:
Does city water in Ottawa require a 5 stage RODI unit given the use of chloramines or is 4 stage sufficient?
Is a high end unit (like Spectrapure) significantly better than a more afforbale option including the those available at hardware stores (ispring, PUR, etc)?
Any brands/units folks can recommend?
Many thanks!

[Dxpert]

I?ve had a BRS unit for many years, I believe they are all the same, the quality/features might vary slightly, but the output product is easily tested with a TDS meter, so really I would go as cheap as possible.

Just a note on Ottawa water, it doesn?t really need an RODI unit, I would just as soon skip it.

[Microscopic]

Thanks for the reply. I appreciate it. If Ottawa water is decent enough (with added conditioner for the chloramines), especially for a fish only tank, that works for me. The fact that RODI systems are often referred as "the best investment" for a tank sent me down that path.
I do have a TDS meter on the way. Is there a ballpark level of TDS that is considered "acceptable", even if not perfect? The 2020 water analysis indiates a TDS of <80 mg/L (ppm) from the purification plants in Ottawa.