Looked up a Gast 1023. They do 10 cfm at low psi and 9 cfm at 10 psi. Rotary vane. And you can figure 14 amps for full 3/4 hp on 110 VAC. The current draw will drop if you run it low pressure, but still will cost. I agree it's oversized for such a small pond.
Unfortunately, these types of canned motors are not required by law to meet energy efficiency "mandates". 14 amps for a 3/4hp motor at 110V is really, really bad. Most of the decent 3/4hp canned motors will have a FLA (Full Load Amp) rating in the 10 amp range at 115V. A really good one will be in the low 6A range, but don't count on finding one in canned motor flavor.
I was looking at a 3/4hp shallow well pump. 12.2 Amps at 115V, Yikes!!! Then I saw one that was listed 5 Amps at 120V, and about fell off my chair laughing
When did the Chinese come up with single phase PMAC motor technology and able to offer a pump/motor combo thru a nation wide distributor for about 75 bucks
Electric motor voltage schemes for the USA are going to be 115/230/460VAC. That's because most places in the USA have power schemes of 120/240/480VAC.
Quite a bit to this electric motor stuff, but the vast majority of people are stuck with the offerings at hand and gravitate toward what is the least cost to initially purchase. Could be really expensive to operate tho.
Another thing with these canned motors (a motor made specifically for a product that won't fit anything else), is that they list the HP rating as what it consumes, not what it produces at the shaft, as it should be.
I got a close-up of a 3/4HP rig as stated with the stickers on it. Thought the calculator in my cell phone was on the fritz. Long story short, the HP rating is what it ate, not what it produced. Compressor motor was actually 1/3HP, not 3/4HP
Yep, kinda stuck with the offerings, but people make the best of it.