hi could anyone here please give me the exact outer dimensions of both the 24w/24" single and twin units? i have a 180 litre aqua one corner aquarium of which the supplied lighting is very poor to say the least. i'm midway through building my own unit with planned arcadia starters (not yet purchased), but these units are not cheap, with the added cost of reflectors. i have only discovered that using 4 of the ready made hagen units (switching on and off at different times to replicate daytime) would work out a lot cheaper. the plan is to put 4 in a row over a 60cm x 30cm orifice in the hood, but if there is not enough room, then obviously they are no good to me! cheers and thanx in advance, bazz! b.t.w. could i just wish some good luck to everyone involved with rescaping at "the green machine" of what was my favourite aquarium in the universe, sad to see it go, but i know it will be better than ever!