Looks like a few differences. Pump location - the Octo is under the body and the WM is next to it and output adjustment method - the Octo uses a slide tube and the WM a gate valve. Looks like the WM has a line to drain the collection cup and none on the Octo.Wow. Howcome that one is so much cheaper than the wm model. There has got to be a diffrence.
yes in that situation with air ball valves are the best. but for skimmers and water type valves it is gate valves all the wayi dunno, i tend to like ball valves for most of what i do(high pressure airlines and things like that)