Hello! I am planning on making a mob farm with the basic water flushing system, that follows the basic idea:
You build spawning platforms, and in the center you place a dispenser with water in it, with an observer below that to activate it. And you tile this with many platforms. When the bottom observer is triggered, the water is dispensed on the bottom platform, which triggers the observer above it, activating the dispenser above that, and so on and so forth, making all of the water dispense on each of the platforms.
Before actually building this in survival, though, I was fiddling around with the idea in creative to make sure it works and I understand it, but I ran into an unfortunate problem... When I put a redstone torch on the bottom observer to trigger an update, it works, making water spread onto all three of the test platforms. So yay, that works. But then when I break the torch, and place it again, to send another block update, the water only goes away on the bottom layer, leaving something like the image. Why isn't all the water going away like it's supposed to?
Also, ignore the redstone dust in the image. That's not attached to anything and was just left over from me trying something else.