I used a commercial (hobby grade) one for several years in a lagoon in Mexico. It was called a hookah, should be able to locate info Googling hookah diving gear. It had a pair of 30fot hoses and on demand regulators. That was back in the early 90s and was about $700.

The main hose hooked to a weight belt with a spiral hose leading to the regulator. It had a metal SCUBA flag mounted on the motor that acted as a sail to keep the intake/exhaust in proper alignment. The whole thing floated on a truck inner tube.

The whole rig weighted around 70 pounds and was easy to use.

It finally wound up being used when we cleaned the bottom of our boat.

1/4 & 3/4 acre ponds. A thousand miles from no where and there is no place I want to be...
Dwight Yoakam