This schematic is easily expandable by adding more water wheels. Each additional pump is 32SU, and each additional piston is 16SU.

It is only unload-proof if the whole machine is in the same chunk, or if all the chunks the machine is in are somehow guaranteed to be loaded at the exact same time.

If you have not made the unload-proofing module, remember to turn off the farm before you leave the area or the world. If you forget, you will have to turn off the farm by switching the lever on, attaching a handcrank to the other side of the pistons to retract them, and replacing the cobblestone generated in front of the retracted pistons with the furthest trapdoors.

Specs:
- 1 slime ball
- 0 brass
- 1 frost walker (any level) boots for unload-proofing
- 7.2k activations per hour, multiply by number of pumps to get rates
- Easily expandable