Basically, you drill near the edge, then you can adjust the water level by taking it off and turning it. So, if you want the water level really high, you put the hole near the top. If you turn it, and put the hole near the side / bottom, you'll change the water level - this way, you have total control and only need one rubber end per pipe.Thanks man I was looking to hear that, that seems like the most efficient thing I could do given my situation. Nice and simple and the price of low, thanks. I actually was thinking the same thing, bring them off the slop so the water would settle instead of run. What do you mean by drilling a hole near one of the edges?