I could'nt find a 2"x1/2" adapter for the lid, all I could find is a 2"x1" adapter which means I would then need to add a 1"x1/2" adapter to that as I will be running 1/2 PVC to plumb it (it makes no sense to go larger as the most I will be able to drill the outlets is about the same I.D. as the 1/2" PVC). Using all those adapters would be not only bulky but pretty ugly also, so I went with a 2" plug and a 1 1/2"x1/2" adapter. I chose the plug also because it has about 1/3 the threads as the adapter and seeing as it has tapered threads, I did'nt want to cut it down, in other words, this way would stick out about 1/2" less. I then drilled out the plug to snugly fit the 1 1/2"x1/2" into it, I also cut about 1/2 the height of off to keep things compact. I think I'm going to run the SCWD upside/down to keep the flow to it as unrestricted as possible. I have a 90 screwed into the top so you can see how it will work a little better (it was the only screw in fitting I could find in my collection of fittings).
