The tool that you are referring to is used with another type of pitless. This looks just like a spool type pitless that only gravity holds in place - looks like they left a short nipple and coupling already threaded into it for some reason......I'm not really sure what the black poly is, other than a pipe to pour chlorine through. I have done this to chlorinate a well with a spool pitless so you don't get the chlorine all over the threads you pull from. When I've done it, I've just stuck the pipe in the wire passage enough to get the chlorine past the device. I've never left one in though, so as not to confuse anyone trying to pull the pump.