By deeper, I assume you mean how tall the tank is, because at only 7' of depth(front to back) I feel that the tank is just large enough to house sharks. as for the height, at 8' tall, of course cleaning is a little different than your average tank, thats what SCUBA is for.... I dont understand where your comming from with "needlessly risky"??? how so? Are you speaking of swiming with the sharks? They are pretty mellow, and even if I went with black tips and white tips, I wouldnt have any quams about jumping in with them. The tank is going to be an open reef shelf with sharks as well. With the 8' of height, I will actually have some room to create a reef shelf. If I go with a single front pannel of 14'x5' it will be of the new scratch proof acrylic, and it will be a single sheet with a thickness of no less than 2". Why fiberglass??? Because its the best material the tank could be built out of, FRP is also a good material but the fiberglass will be nice, baby butt smooth inside walls of any colour, amazing strength, very light weight for its size, easy to insulate,(it will be heavily insulated)and its portable. When I move, it moves, cement is a last option for big tanks, it is a pain in the butt to work with for plumbing, hard to seal, pain to repair settling cracks, we can build 50,000+ gallon free standing tanks out of fiberglass, I wouldnt consider cement unless I was going over 50,000 gallons for freestanding, cement is also silly expensive to do properly. With fiberglass you can also make any shape of tank you want, its great stuff! The mini Hammerheads are Sphyma Tiburo, and rarely grow over 3'-4' and they do not get nearly as heavy as the blacktip.