Cong I see what you mean this is my take.
The only reef test kits I own are temp and salinity, that's what matters. I can keep any coral that will physically fit inside a pico reef alive for a decade off just those two params because I change all my water once a week, easy reset for pico reef.
its not that a full water change is required, its that its ok to do if access allows it. a 50% in your case is specifically associated with the longest running 3 gallon documented tank you can likely find on the internet, El Fab's 3 gallon pico reef, google that.
For the entirety of his tank, he only changed half the water 1.5 gal 1x a week, dosing nothing ever other than feed, for 3 years. he tested only salinity and temp.
I realize there are nine params you can test for reefing, its just not required past those two. test away and match away if you want, or not, since the examples provide for that. If I had a three gallon tank and not a one gallon tank, 50% weekly and low fish stocking so you don't accumulate waste would work fine and not be too much work. The animals we keep in pico reefs allow for that variation.
to show you how unimpactful water changes are, my own LFS makes my change water and they skip brands all the time. My tank goes from oceanic salt, to kent, to esv, to IO, to reefcrystals, on and on 100% instant water change, and they all have different params. even pH isn't needed, nothing past temp and salinity unless you are just enjoying the techy side more than the more work side.
the reason param matching isn't required in pico reefing is because all known salt mixes aren't lethal to corals, and corals adapt to param differences among salt mixes, for pico reefs. If you use a skimmer or not doesn't impact the need for testing things either, its just an option among options and not common on the smaller tanks.
