For me the biggest leap was from T12 tubes to HQI lighting but them I am only 36 years in this hobby much less than Paul. I recall seeing my fist clown fish and was smitten with their beauty and movement so they were my first marine fish. There was much choice in salt but it didn't seem to matter much given we only kept fish, later came a few soft corals. My first nem quickly followed soon after I bought my first cumbersome HQI with a 250w 4300K lamp and I thought it was the bee's knees, later I got a 5400k lamp > I managed to keep a Magnifica when all the books etc said it was impossible to keep one more than a couple of weeks . You can imagine my delight when my clowns spawned under it. I later sent Albert Thiel a slide of it and he used it on the front cover of his book "Ten Easy Steps" I still have that book although a bit tatty now. Choice of marine fish was limited and when we eventually we got more exotic fish they would be mainly almost impossible to keep butterflies that nearly always refused to feed on the limited foods we had available. We certainly don't know how lucky we are today and are spoilt for choice when it comes to fish and corals.