You will have to use an overflow, which is a pain! I had one and several floods and new tank later, my tank is drilled. My advice to you, and I'm serious - is drain the tank and start over. If this is your dream tank that you want to have forever - start with it drilled and make a sump.

Is there a good saltwater fish store in your area? They could probably advise you.

You can also look on the newbies forum on www.reefcentral.com.

Good luck!