Hanging my light

[Eyford01]

My lighting is one single ended 250w MH bulb in a DIY (but not by me) reflector that is a square metal tube with a bent piece of sheet metal to direct the light, what I had done before is run a length of furnace chain through the tube and hang it from the ceiling, now that I've moved the ceiling is cement and I can't get a hook in it, any ideas how I can cheaply hang this thing? Rightnow it's balanced on top of a 15g on top of the DT but I need that 15 for something else now