What size would you recamend I can't go too big but am also not wanting to give up. It's been doing great now for about three weeks with 1 peppermint shrimp, live rock, live sand, and real filtered pacific ocean water. Only a canister submersed filter 90 gal. per hour no heater, but I have kids and my home stays at a steady 80 degrees; water temp hasn't droped below 78.