Jag3365
You're welcome to ask any questions you have
I don't disagree with tangsfornuttin regarding one pump being more efficient than two.
I chose to use two pumps for specific reasons.
One reason as you mentioned Jag, I have a back up.
The chances of both pumps failing or not starting up at the same time are less.
Second reason - I run the 9.5 all the time, and have a timer kick on the 7 now and then to stir things up a little more.
It's not a wavemaker by any means - just some random changes in water movement was what I wanted.
And no powerheads in the tank either - I don't like seeing them, and I don't like maintaining them.
If I want a different flow pattern - I reach in and turn the flexible nozzles on the spraybars.
Not very sophisticated - but works okay. I rarely do this unless I add a new coral specimen.
If you go with two pumps Jag, I wouldn't drop down below 500 gph on the dual Lifereef. Flowrates less than that may allow some bubble formation in the U tubes.
Bubbles accumulate and in the top curve of the U tube(s) and if allowed to grow too large - the air gap can cause loss of siphon.
I've run the tank with the Mag7 only while doing pump maintenance on the 9.5, and it works okay.
But I wouldn't run it with the Mag7 only for long periods of time.
Just not enough tankwater circulation for my tastes.