Hey dude. I recognized the color scheme of your design and then remembered your post back from August... I commend the effort and thought you've put into this but its kind of the same deal as what you had before... It appears your trying to reinvent the wheel once again.
There's a ton of reasons to run DWC totes and not an undercurrent system for veg. Lower cost, no need for a chiller, no connections to leak, less water, less space needed to veg more plants, time saved on building, yadda yadda..
Even if this was a flowering setup there's some things that are backwards with this design. Too many lines and improper placement to be an efficient recirculating system. Flow decreases with every corner it encounters.
You should be pulling water through the system with the pump and discharging into the epi using a single line, not the other way around. That way you're getting the waterfall effect and adding in DO to the nutrient solution. Assuming how you have it the 2" bulkheads are tied into the bottom of the epi. Now your relying solely on airstones to add oxygen. You would only need a 1/10 HP chiller for this setup.
Not sure what the purpose of the sample pot is either given your epi is outside of the tent and would do the same thing.
One of the many great contributions of this forum is the tutorial Heisenbeans put on here to help people build and operate UC systems. Seems counterproductive to not use that information to build a similar system as the rest of us have.
13 gallon buckets for a 6x6 is far beyond overkill. I've got 4' - 6' plants in my system with 4 gallon buckets.
BEst of luck regardless
