Thanks for the video, shows a lot.
I've been skeptical of using air lift to power a vac. I like the volume of water air lift can move and am considering it for my next pond. But for a vac, I've been skeptical.
However I'm start to see some real pluses. Biggest is in silt removal mode there's no need for any leaf trap. That's like have the issue with water pump type vacs. Plus the leaf trap and pump can be a bit heavy and awkward and have to be inside the pond. Electric is far from water is a plus. Air compressors are very handy tools so it would be a multi-use tool.
I still think two separate vacs are better for big stuff vs silt, but no denying replacing the exit hose with a mesh bag for for vacuuming big stuff is clever and does work. When I vacuumed good size ponds with the
Muck Mop I was using a bag that held 1/2 to 1 bushel of leaves and string algae so having the bag on the side I'm not too sure about. But maybe that's nothing, and besides, this was just a prototype. More tweaks to come I'm sure.
I think what worry's me is power. No question air lift has power enough to vacuum. I can see clearly in the video how it is vacuuming silt off the bottom and that's exactly how well a water pump vac would work. I wouldn't be able to tell the difference.
My worry is the 1/4HP water pumps I was using had a lot of power. That doesn't mean it vacuumed better. It means the power overcame a less than perfect vac design. I could use swimming pool hose no problem because I had power enough to push small children thru the hose. A leak here and there, no problem. Hopefully none of these will end up being a big deal. Will be interesting how ever it goes.
FYI, because you have a raised pond I'd assume your vacuum could create a siphon. If you laid the end of the outflow drain pipe on the ground you might be able to turn off the air and keep vacuuming. I don't actually think that would work for the drain pipe, but could when/if you try swimming pool hose. That would be another plus that air can do that a water pump couldn't or at least wouldn't be easy. It would be an interesting test. But using the board thing you have would also be a good test to simulate a pond that wasn't raised.