I guess Im kinda partial to "taller" tanks, as for my personall feelings on the matter, I think people are way too worked up about tanks over 20" not getting enough light. I feel that 24" great, 30" is still great for a reef, and 36" is still ok for a reef, mabey dont put all your sps on the bottom, but still not that big a deal.... these are my personal feelings on the matter, and I know some will disagree with me, but thats ok. To backup my feelings, out of all the "nice" sps tanks I have seen, I cant recall any being less than 24"tall, infact most were 30" or taller. some tanks that looked nice to me may have been 20" but that dosent take away from the fact that much taller tanks look just as good, in my opinion better, and health and growth is not a problem in said tall tanks....