We are in the process of setting up our first octopus tank and would appreciate a review of our plans. We have decided to locate a briarius as our first critter for both its size, availability and warmer water tolerance (no chiller this go round). Tank: 45 gallon hex acrylic (roughly 2' dia x 2' tall). We are moving the overflow and inflows to the back (was in the center). Overflow is 3 inch square "tower" with a short stand pipe. I plan on putting a sponge in the overflow to prevent accidental entry but suggestions here are solicited. Return will be 1.5' PVC straight pipe with holes drilled along the length of the pipe placed behind the overflow. Here too, we would like suggestions on concentration of flow (top vs bottom vs even). Cover: Solid acrylic top cut to fit the full opening (there is a 1.5" lip around the tank). I would like to hinge the top for ease of access if I can find a plastic hinge - possibly an aquarium light cover hinge will do the trick if I can find one to fit the acrylic thickness. The cover is not constructed yet so I have options here. What amount of weight would be enough to keep it in place for an adult briarius? Sump: unknown volume but probably only about 3 gallons of actual water. We plan to use rubble live rock, poly-bio filter pad AND charcoal in the overflow filter section. It will house a protein skimmer on the return side. No plans for plant life but we could add a light and a small amount of macro algae if recommended. Overflow sponge will prevent large things from entering filtration (but will it prevent the octo from making the trip?). We will put a two fan Azoo unit over the sump (this unit effectively cools our 4' tall 30 gallon hex without sump about 3.5 degrees from abient, maintaining the tank at 72.5 in a 76 degree room). Substrate: Live rock and live sand from the prior set up as FOWLR. Rock is currently in our cure tank, some new rock will be added and is expected to arrive this week. The plan is to line the back three walls with LR and Gorilla glue the major pieces together and to the overflow (I know this will kill a small secion of the rock but have had good luck with this glue creating live rock walls on egg crate). The intent is to create many nooks and crannies of varying sizes to allow a choice of dens. Will it be self defeating if the "back" of a cave is against the acrylic rather than rock? We plan to black back the three rock sides. The remaining half of the tank is planned as live sand bottom with scattered LR for rearrangement as desired by the occupant. How deep should we make the sand bed? I believe a functioning DSB is not an option for our critter and recommendations for a reef tank are either 1" or DSB of 6" or more. I would think a 1" depth would not be suitable so we are asking for recommendations. Lighting: 2 x 65 watt power compact bulbs, independently switchable. Red LED night light, unsure of wattage or lumens but it is strong enough to light the whole tank for night viewing. Is it true they do not see red and that we may be able to illuminate the tank at night using only the red light? Would night lighting discourage daytime activity? Toys: I have ordered two plastic "ice cubes" that have sealed internal lights, they are FDA approved for use in human drinks and can be frozen. The thought is to see if it enjoys playing with something cold and/or something lighted. I have found one with multiple colored lights as well as one with only one light color. I have also seen but not purchased rubbery eels with holographic strips inside. Would this be too dangereous since the rubbery material my be sampled and possibly ingested? Two other considerations are to put live shrimp inside a bristle worm trap and a plastic transparent "Easter" egg. I am also posting a second thread on our intent for critters but would like to contain this posting to hardware. All critiques and suggestions are encouraged and welcomed. Thanks in advance (see Nancy, I said I would post ;>). "D"