First Time DWC - 4 x Purple Glue

I am beginning this a little before I plan on going to flowering. This is my first time growing - enjoying the new Canadian laws Bought these feminized purple glue seeds on a whim one night, and immediately got caught up in the hobby.

Setup:
4x4 Grow tent
600W HPS & MH
1 x VIVOSUN Air Pump 1110 GPH 8 Outlet 70L/min
4" Netpots
4 x 2" Diameter Air Stones

Plants are numbered 1 to 4, clockwise from the bottom left corner. Water was last changed three days ago

As of today these are the plant parameters. Using 1:1:1 Micro:Gro:Bloom currently:

1. pH = 5.7 ppm = 1282
2. pH = 5.8 ppm = 1055
3. pH = 5.9 ppm = 1239
4. pH = 5.6 ppm = 1055

All started from seed, about 2 months ago. Just bought a house, so I should be making a more permanent setup soon. I plan on running the whole shebang using a web interface.

Latest pics.

About two weeks into flowering now. Bought a new home, have a huge amount of space to play around now. Some pictures are in weird positions or with other cameras because I was moving.

Added a gif of my cactus and black garlic sprouting.

Working on automating the grow still. I am waiting for an ADC to arrive so I can add an EC meter and pH probe to the bucket. I call this my "working reservoir". The buckets with plants will have valves which open and drain to a sump. A pump lifts the water from the sump to the working reservoir for measuring and maintenance. The working reservoir is physically higher than all the other buckets. When the nutrient solution is ready, a valve opens draining the working reservoir back to the bucket. Then it will move on to the next on a maintenance cycle.

I am using a raspberry PI for the controller. I am using Flask for the webserver. The plan is to remote into my computer, access the webserver, and use that to adjust target pH, ppm, and nutrient ratio by barrel.

I chose this approach so I would only have to buy one set of good sensors, instead of trying to by them for each bucket. I think it will keep up fine with four buckets.