Steve Bashsea has actually changed the design a little from the original one. They no longer use a valve at all, they put the outlet at a perfect height to achieve the proper level in the skimmer with a range of pumps. Steve told me they just have not updated the website since they had issues getting the gate valves they liked. Also new design keep the user error issues down. My 8-24 can use a sicce 7-9 or equivalent and work properly, using a larger pump for higher bioload. I like them because they just work no fiddling no break in period plain and simple. That picture that I posted was less than a day into its maiden voyage. Why are they so huge? Well thats one way they work plenty of time to get those bubbles doing what they should do. They can be use internally or externally just have to account for head loss from the pump if the skimmer is farther away. Really though they are not too huge they make a 6" diameter 24" or 30" tall an 8" and a 10" they also make ones sized for monster systems like coral grow facilities or zoos. At one point I had roughly 1200g with a 6' tall 18" dia Bashsea custom skimmer took two very large red dragon pumps to run it.
Edit and two people to carry that beast.