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Nice work. Love the built-in charging and power outlets.
Nice design! I had made something similar but not so portable. I attached a toggle switch and duplex outlets to a leg so I could turn the saw on & off without reaching under the table. It can also be used as a job site extension cord.
You can change the Adruino program to only open on a 4 digit passcode. Also alter HC06 default paring code making it harder to "pick" this lock.
You don't mention using the check valve. It may not be required as long as the air pump is mounted higher than the water level.
Here's one using a submersible pump. You can use the inverted lid design used in this instructible to keep cost down. https://www.instructables.com/id/How-to-Build-an-NFT-Hydroponics-System/