i copy this sump i build from 55 gallon glass tank the sump.
i hold up the center piece from falling while the sealant is drying with 2 piece of my drain pipe they was 1" the silcon dry after 15 minute and then i pull that pipe out and glue the last one. (you can use any other object and when it"s dry pull the object out and glue the last glass)
all my pipe, unione valve , t connection ,elbow and ball valve i bought from home depot if you can use the hard pvc they are better and cheap to.
i plumb all the pipe that if i want to disconnect i can do this quick and i can move the sump out . i will add some old picture here to give you more idea hope it will help and good luck.
(the picture that i post before are the update , and how the sump look like right now)
i add on the pipe filter sock 100 microne and i collect a lot of detritus on the filter , more then that there is no bubbles in the sump . the important thing you must to remmber this : never put the skimmer pump in the area of the drain pipe ,where all the water go down when you put the skimmer position the pump in the quite area that you can in this case your skimmer improvement will be twice a lot of ppl don't do so and they don't know why they don't see a lot of foam in the skimmer collection cup....