"Aquatic-Care" verbositized:

Gary,

Manufacturers ratings are based on an unrestricted flow with little to
no resistance from the piping.
In other words, they use very large pipes for the size of the pump
outlet. Normally more than double the size of the pump outlet!

I would have guessed wrong. I thought that the pump would be tested with the
same size hose that the connection called for. This is misleading..!! Makes
it tough to choose a pump properly. I will stow this tid-bit of information
for my next installation.

I would venture to guess that a Maxi-Jet's flow rate at the given
height for their test is done using the Maxi-Jet output feeding
directly into a 1-1/2 inch to 2 inch standpipe.

I used all 1 inch tubing for most of my reef plumbing and it made a
BIG difference, especially on the feed from the sump up to the tank.
A 3/4 inch hose, after about 3 months of use, even with monthly
cleaning, really seems to slow down quite a lot.

If you check in the dishwasher section of your hardware store, you
will find a black neoprene reducer with two hose clamps to bring you
from the output size of the Maxi-Jet up to 1 inch PVC. I have not
found one yet that goes from the output size up to 1-1/4 or I would
have gone that route instead.

Another alternative is a rubber grommet placed into a PVC pipe cap on
the lower end of your vertical lift tube. This would be slid over the
Maxi-Jet's output fitting.

You've probably heard me say this before, but keep the current in your
tank with the natural flow of the water. In north America this is
counterclockwise, down under (Australia) it is clockwise.

TTUL
Gary