I have a tree root which will stand upright on its own but its 16'' high and i want to make sure it doesnt topple over. Not sure if im going bare bottom yet. I have a piece of slate i could silicone it too but its not perfectly flat what should i do silicone it to the tank base or find an off cut of glass to use instead. Or if i use gravel can i use the slate and bury it, not sure if this route is good as there would be gravel pressed under it, can this crack the recessed bottom of the tank? the root probably weighs 3-4lbs and the slate is probably of similar weight