how to have a black overflow ?

lo guys.. i will have an overflow for the tank outside the tank.. i mean.. will cut a piece of the left side of the tank and it will be the overflow.. but then.. i will see the overflow from the tank..

how can i make it black.. so i wont see the water going down that side and fill the overflow etc etc.. ?

i thought about to put a pvc layer.. but then.. i will see the glue/silicon i used to put it there.. or worst.. i will have water between them that will make nitrates cause isnt moving..

sob.. no idea on how to make it..

 

My overflow came in blk, you dont see the water flowing in, but you do see the blk silicon that was used. I really dont see a solution for that other than wait until it gets covered by coraline.

 

lunatik.. you may have find a solution i can use the black silicon to "paint" then inside of the overflow ... secondary .. algae should not born inside the overflow kepping it cleaner then usuall...


tnx