Mag drive size recomendation.

[angler man]

My friends wife asked me what he would want for his tank for Christmas, I know he mentioned a new return pump so I was wondering what Mag drive size would be appropriate for a 72 bow front. He built his own overflows so it's not a drilled tank with the all-glass stock overflows.
Also, I have a 92 gallon with the All-Glass overflow, what Mag should I get for my tank if I wanted one as well?
Thanks!

 

[scsinet]

One megaflow or two?

 

[gill again68]

There are a few questions to be answered to get you that answer.
1. How much length from the pump to the return point. This will = head pressure.
2. How much flow will the overflow handle. This will = max flow.
These 2 things will help you decide what pump to get.
Example of mine is:
I have a 90 gal with 1 mega overflow.
Overflow will handle 700 gph give or take.
I have 4 1/2 feet to the return points. That was my head pressure. This was suppose to eat up about 200 gph. So with that I chose a 9.5 or 950gph pump. That pump I figured would give me the 750 gph I was looking for. It turned out to still be a little to much. I had to close off my valve after the pump to slow the outflow. So there is a good example of what not to do

.
There are some calculators out there to help you with this. If I find a google link I will post. Good luck.