My first edition of a new series called Moth towers that i built this week it is redstone controlled so that if u want to explore the items would drop to the void and be destroyed. The way the mobs spawn is that they are on a pressure plate, they get pushed onto the canal and cannot get back on where they lead into a hole and fall to their deaths, there is also a lava blade incase some mobs dont die, there are about 38 floors of spawning space about 18 spaces
so 38x18=684
now mob farm drops:5000 drops without spiders!
By the way: Moth=mob factory but because mof wasnt a word i made it moth towers

PROBLEM!!!
because of the 120+ block height mob de spawning habit, this project may be discontinued if the new taller section fails to work, but for the time being i've fixed the redstone