BRS did have a video on this; it was many, many years ago, though…
If memory serves correct; BRS claims that their carbon blocks physically weigh more than competitors (more carbon)…
— the GE sediment filter is the gold standard, it’s actually graded between 1and .1 micron, basically just a better sediment trap…
The idea here being that your sediment filter should actually be replaced most often, followed by carbon block, then RO membrane(s)…
— the sediment filter keeps the carbon blocks from prematurely clogging
— the carbon blocks keep chlorine/chloramine from rapidly degrading the RO membrane(s)
Knowing this, I actually have a 5micron GE sediment prefilter, which I change every six months; allowing my 1micron sediment and dual 1micron carbon blocks to be changed roughly yearly! — this saves $ in the long run as RO membranes last 4+ years (and are by-far the most expensive component)!
— try ignoring the cost of the RO membranes in the replacement kit and looking at the cost of just sediment/just carbon… they are significantly cheaper than the RO membranes!