what on earth is this

[g1mme]

Hey guys
I got given a tank 660l (175 gal i think)
and it has this box above the tank, but still under the lid. at first i thought it was a breeding thingy ma boba but then I saw that there are gaps in between the boxes and there are two inlets at either side of the boxes?
I cant take a good pic because of its loccation but it looks kinda like this
Yeah, so please help the confused newbie!

[g1mme]

http://i1218.photobucket.com/albums/...e/23d20332.jpg
http://i1218.photobucket.com/albums/...e/d0f17a3b.jpg
Some pics

[g1mme]

Got some pics for you all. Nit very clear. Taken from my phone!

[BillD]

Looks like an overhead filter. Water goes in one end, passes through various media and out the other back to the tank. It could also be used to grow plants possibly, sort of like an aquaponic garden.