Gar B3ar - As already stated your 300 gallon is way to small for any requiem shark. Scalloped Hammerheads and Great Hammerheads need systems in the tens of thousands and hundreds of thousands range. The Bonnet Head needs a tank / pond size of about 4,000 gallons however its highly not recommended a amateur takes on the task of trying to keep one. Before you go on any further, I suggest you order and read "Aquarium Sharks and Rays" by Scott Micheal. This will give you some basic knowledge on how to begin your shark keeping career. With your 300gallon you have 2 options for inhabitants unless you garuntee you will be upgrading in the future. These two options are Coral Cat Sharks and Marbeled Cat Sharks. Both reach maximum lengths of about 24". When setting up a Shark tank keep the following things in mind, leave as much space open as possible, keep the live rock to a minimal, however provide enough liverock to give the sharks some shelter, use the finest sand you can find, perferable an aragonite type sand, anything too course will irritate the sharks belly and can casue infections. Another thing which is really important is filteration obviously. You will need lots of flow, perferable 10-15x your tank turned over in an hour. By this I mean, since your tank is 300 gallons, in one hour your tank should turn over about 10x, so in another means you will have about 3000gph of flow in your tank. On my 330gallon I have 12,500gph roughly. Another thing you should keep in mind is a closed loop system. Powerheads work but sometimes can release eletrical currents which in long term can kill the shark because they are very sensative to any free roaming electrical currents. Also as obvious as it is, you will need a very large skimmer. Perferable one rated for 2-3x your system. Since your tank is 300 gallons, get a skimmer rated for 900 gallon. The larger volume of water you have, the better filteration you will have, so try and run a large sump, possible with a DSB and lots of LR in the sump. I use a UV sterilizer on my system and it works wonders so I would recommend the same for you. Hopefully I have covered alot of your questions. If you have any more pm me, post here, or check out my website in my signature.
Thanks, Brenden
Shark & Ray Central
