Silicone is useless on the materials you'll be working with. it bonds glass to glass well but thats about it. Is it worth doing?....well personally when ever I see a set up like your talking about building I hear the theam song from Sanford and son running through my head...IMO...no. Just use the tub the way it is and view the fish from above or use the tubs for breeders. As a main display...it's just too ghetto for words....