We've discussed this before I've grown in autopots for years and you will never get a complete dry spell they will always have a small amount of liquid in the bottom as the only time mine are dry is if I had a blockage. Also I've just upgraded to to new 2020 valve and floats and they act the same
I know that. My trays were staying at half, never going below or above.
Here's a quote from @Olderfart, "How the valve should operate: If the Autovalve is operating properly, it will fill the tray until the water is about 25mm deep, and not further. It will then not refill the tray until it is virtually empty. Virtually empty means that no more than a couple mm of water is left. "
So I'm troubleshooting my setup so it drains until theres only a couple mm of water left not stay at 50%-or-so capacity.
Also to note, I have the 2020 version. I just bought the autopots a couple months ago.
Hopefully this helps someone who is checking in on this.