Don’t eyeball the sludge in your dark manure pit anymore. Make your own laser meter on a stick to determine what’s left in your pit the next time you pump it out, suggests Ted Funk, retired University of Illinois Extension ag engineer.
The concept behind the laser meter on a stick is simple, he says. The laser shoots a beam between the slats and reflects off whatever it hits first—liquid, crust, solids or foam. The distance meter is mounted on a portable stand built of PVC pipe and fittings, and the length of the stand puts the meter up at a height that is convenient for the user to operate and read.
“The laser meter gets you the numbers quickly, anywhere in the building,” Funk says. “It’s also easier to maneuver than a stick, is cleaner and more biosecure because it doesn’t enter the pit, and it can do a quick survey anywhere in the building, not just at the pumpout port.”
Go to your nearest farm store and buy a laser-distance meter and any of the following supplies if you don’t have them on hand. The stand, starting at the part that rests on the slats when you take a reading, is simply a standard PVC toilet flange mounted upside down with holes in the flange opposite each other so you can easily align them with a slot in the flooring; a bushing that takes the toilet flange 3” down to 1.5”; a length of 1.5” PVC pipe a little under 4’ long; and a standard 1.5” coupling.
Attach laser-distance meter to the end of a pvc pipe and cement one end into a toilet flange.
Line up the slots on the toilet flange with the slots in the flooring.
Keep in mind that the coupling needs to be carefully notched to accept the distance meter while holding the meter vertically aligned with the pipe. The laser must be centered in the stand so you can easily and reliably point it between the slats for a reading, he says.
The meter readout will be upside down, so he suggests getting a meter with a backlit display in case you are operating in a poorly lit area of the building.
“A data storage feature on the meter is also nice to have, so that you don’t have to fumble with paper and pencil while you are taking measurements,” he adds. “When you get back to the office, you can plot the depth readings on a graph.”