i have a 72" glass tank that is 12" wide to house my two aquatic turtles. it was custom built specifically due to the fact that the last tank i had was wider and the big turtle's "turtle topper" wouldn't fit. she threw a fit, which included picking up a large conch shell and smashing it into the back of the tank, shattering the glass and leaving me with no tank and 80 gallons of water everywhere !! (yes, she is still alive!!) anyhow, when i got the second turtle, in order to keep the possibilities of aggressiveness down, i got another turtle topper....so i have one on one end and one on the other end. that leaves a space of about 3-4 feet that needs a cover of some sort, because the big turtle is laying eggs and for the first time tried to climb out. she hasn't a clue of what is outside of her tank, but she wants out. right now i have my oven racks over the space and she looks like she is "behind bars doing time." i don't like the aesthetics, but it is what it is. i would like to know what light fixtures you have that would accommodate my tank...namely the width of 12"....i need to get something rather quickly, but as these are a bit pricey, don't want to add return shipping costs playing a guessing game. i would be using bulbs merely for lighting purposes; the turtle toppers are equipped with two deep dome light fixtures each....one for heat and one to supply uvb ....it winds up that i didn't need the other topper at all. little turtle basks on big turtle's back and never leaves her side. even when the big turtle is digging to lay eggs, she is right along side of her "helping". there is surprisingly no aggression whatsoever. i had hoped not and believe that although experts can predict behavior 98% of the time, there are always the outliers to the bellcurve (like me) who don't fit the profile. she never snaps, even when the little turtle snags food right from her clutches! anyhow, thank you for providing this service and i hope to get good answers to enable me to make an educated purchase!!!