Pump Size Question

[Dutch-az]

Greets all,

I am new to this forum. And like all noobs I have questions.  We are still in the planning stages of contructing the water feature part of our garden. We will begin digging after the temps get out of the 100's. The pond garden part will be 20' x 16', the other part will be 20' x 22'. The reason for two parts is that the pond garden will be the home to 2 Red-eared Slider Turtles, the other part will be a Desert Tortose habitat. All the plants in both parts will be native to Arizona and/or xeroscape (not counting the water plants of course).

In the pond garden we want to have a small 4' high waterfall dropping into a 3' x 2' x 2' deep pool; a 12' long watercourse, 6" deep and 12" wide; draining into a bean shaped 12' x 5' pond with an average 2' depth. So by my calculations, we will have just under 1000 gallons total (waterfall pond = 45 gal; stream = 45 gal; main pond = 900 gal.).

So with 1000 gallons my pump should be rated for a minimum 500 gph.  But, from what I have read, the waterfall & stream being 12" wide, the pump will need to be 1200 gph (100 gph per inch of waterfall or stream width).

So can I assume I will need a pump rated at 1200 gph because of the waterfall/stream and "ignore" the rating based on total water?

-Dutch

[Dutch-az]

I was looking through the charts in the PondMaster catalog, and now may have it right (or I am totally off).  The deepest part of my pond, where the pump will be, will be 3' and the top of the waterfall will be 4', making a total rise of 7'. The waterfall and stream will be about 12" wide. To have a 12" wide stream, I need to have 1200 gph (100 gph per inch of width) at the top of my waterfall - right?

So should I be using something like the PondMaster MD24 (2400 gph) that delivers 1344 gph at 7 feet?  The next size down, 1800 gph, delivers 828 gph @ 7' (would only be a 8.28" wide stream). With the MD24, I would have a total water turnover 2.4 times per hour.

Do I have this right, or am I off?

-Dutch