You can raise the them so they are closer to the weir that will raise the water level in the rear chamber making it more quite. I would keep one about 3 in below the weir put a gate valve on that one for tuning. Raise the other one until the top nipple is out of the water to break any siphoning. Reefer the the article attached further in the thread what I'm explaining would be a bean animal without and emergency in my opinion the best way to have a silent tank