Hello and welcome to the channel. I am not sure what you are trying to ask. Yr is an abbreviation for year. If you are asking the age of our tanks, my newest tank started on January 29th, 2020.
Welcome to R2R. Not sure what you are asking so more info needed. Lots of knowledgeable and helpful people here who will support and advise you when needed.
I had 2 hexagon tall tanks -1 for seahorses about 25 years ago, but I wouldn't due that shape tank again due to lack of hiding space for equipment (canister filters back then, would use sump & refugium these days) underneath tank. Rectangles have fewer corners and more space in cabinets underneath.
Bought them new, don't recall how much. Sold them cheap used after a few years when I was moving again, but I don't recall how much for that either