So I made a kelp farm based on youtube videos. Sadly the pistons deactivate water blocks rendering every water flow and float based farm useless.

What I expected to happen was...:
Items would float up to the water surface normally.

What actually happened was...:
Items stuck floating on the active water block.

Steps to Reproduce:
1. Build any water float based structure.
2. Use a piston in the water.
3. The water block that was "pushed" by the piston will refill with water but the new water block won't be active, cancelling the floating physics and items won't float up to the surface.