<a href=showthread.php?s=&postid=11519064#post11519064 target=_blank>Originally posted</a> by scubadoo2
back in the early 90's, some guy was selling large acrylic tubes (10 or 12"dia.) to join aquariums together. Keeping a flow going was a big problem at the time, but he apparently solved it. I'll have to research it, and see if I can find an old link.