Yes, if a tank has a center brace, it needs a center brace. Tempered glass is thinner and more flexible than the old thick glass. My center brace broke on my 55 and the long sides of the tank bowed out so that the center was 1.5 inches wide than the ends. If I hadn't emptied it, I'm sure it would have started leaking. From your measurements I get 35.5 gal. 36X12 is a standard 30 gallon long stand. There are also higher tanks that have the same footprint. You can also buy little plastic feet that will raise lights off the tank.