Hi guys - Russ Romme with Buckeye Hydro here.
I wanted to comments on a sentence in your write up: "Number of filter stages (more is better??). I chose a 5 stage system. The more stages, presumably a greater filtration level."
We find this concept is a common area of misunderstanding, especially with first-time buyers of RO's.
Consider a three stage system consisting of a sediment filter, carbon block, and RO membrane the default configuration. Add filters to this configuration only if warranted.
If you want to add a pressurized storage tank to the system, then you'll also need an inline taste and odor filter.
If you have chloramines in your water, it makes sense to add a special chloramine-type carbon block before the membrane.
There is a price you pay every time you add a filter. First, you'll have to pay for the filter, and then you'll have to pay to replace it periodically. Next, if the added filter is before the RO membrane, you'll lose a bit of pressure pushing the water through the filter.
Take home message: Understand what each filter does, and don't assume that "more filters=better filtration."