My tank was BB so no worries about the sandbed. The longest length was 45" with a 14" segment at the end (it was L-shaped). It wasn't a true calfo manifold as it wasn't all one continuous "loop". I split the manifold in half with a SCWD so that only half of the "loop" would fire at a time. Worked quite well, but too bad the SCWD adds so much headloss to a pump. In retrospect, an Ocean Motion 2 way would have been better as you can use much larger pumps with it.
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32"x32"x20" Cube-ish tank
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