I think it's important to remember that flow through an orifice at a given pressure is not the same as the head pressure produced by that flow rate going through the orifice. The former looks more restrictive, but it's not what we're talking about in this situation.
I also think it's important to mention that an orifice just refers to the opening it goes through, but not a length of pipe. A length of pipe will produce more friction because friction is accumulated over a larger surface area.
I could not test exactly what you requested in the span of time I had, but I used what I had. It was a reservoir of RO water, with a magnetic drive pump attached (
Iwaki WMD40-RLT), and the outlet was at about the same level as the water in the reservoir. The pump is capable of producing 9.3 PSI and the max flow rate is 14 gpm. I didn't have 3/4" plumbing on it though. I had 2-3 feet of 1" PVC (with a 90, three 45's, and a tee fitting), connected to a 3/4" GHT fitting, connected to 8' of 5/8" ID (0.625") garden hose. This is more-restrictive than 3/4". Human error is involved when eyeballing the 5 gallon mark on a bucket, but it took 24 seconds to fill by my eye. This is a flow rate of 12.5 gpm. This diameter is between those listed on your chart, but close to the range you have for 1/2". So based on your chart I should get closer to 7 gpm than 11 gpm, but I got more than either. It concurs with the head loss calculator I linked though.
Or, you could reference one of the very frictional loss charts you’ve mentioned (which are also themselves intended for large runs of higher pressure plumbing!)
Note that the 3/4” category physically ends, even at much higher water pressures that any residential aquarium pump produces, before the 34GPM the calculator you presented claims 3/4” plumbing can achieve at <6PSI…
Yes, I would not recommend 100' of 3/4" pipe as per those frictional loss charts. Shorter lengths produce less head pressure though, so if it isn't suitable for 100' it doesn't mean that it isn't usable for, say, an orifice. I don't know of any residential aquariums with a 100' run of pipe either.
If you were to use an aquarium pump, which as you mentioned produces lower pressures than the chart shows, it doesn't mean it won't pump anything through 100' of 3/4" pipe. It will pump less water than 34 gpm, which means it will not experience the same pressure. Once the pressure and flow rates of the chart match the same pressure and flow on the performance curve of a pump, that's how you can expect it to perform with 100' of 3/4" pipe.
I sized pumps and associated equipment (e.g. filters, chillers, UV sterilizers, etc.) at work for a few years, with max flow rates from 1-2000 gpm. I would have known long ago if my methods were incorrect. I feel pretty confident that your chart is either incorrect, or we're missing something about it.
I think the suction side of the pump is just one of the potential situations they're listing in the green category. It would be weird for them to display two columns of suction info and four columns of discharge info. It might just be that they're acknowledging you can't have a suction pressure above about 15 PSI due to physics/cavitation.
Okay, I played ball and now I'm passing it to you. Try your own flow measurements at home and compare them to your chart! You might also find that they are different.
