No offense but this system is a disaster in the making.If any of them return lines become clogged than your gonna have a huge mess.I would have a minimum of 1 and a half inch on each bucket that returns back to the res.3/4 is to small.If one of the buckets fill at a slightly higher rate you will also have a mess.
No offense taken, and yes, this is the exact drawback to this design and has happened to me. fortunately, it only overflowed by the amount of water that was in the reservoir and it went into my tent tray that can hold a lot more water. So the disaster was minor, but I knew this was a possibility when I put this system together...
A little history:
When I was trying to decide what kind of DWC design I wanted to build, I though it was a good idea to have the water/nutes come from the bottom of the bucket, flow through the root ball, and flow out the top (at the desired water level) on the opposite side of the bucket. I couldn't afford an UC system, they want a left nut and a first born son for a 6-node system.... so I did what I could with buckets, tubing, and other inexpensive pieces.
This system works if you keep the 3/4" exit ports clear, but, yes, the buckets will overflow if the exit ports get clogged with roots. I also thing the water flow is a little more restricted than I like with the smaller tubing in the flower tent. There is also much more distance between the buckets in the flower tent than my veg tent so the return tubing sags and causes more of a water resistance... It's all an experiment for me and it's all fun and games until you're on your hands and knees with a sponge soaking up water from the tent tray };-)
The buckets do fill at a slightly different rate but they are pretty symmetrical, the result is the bucket water levels are slightly different but that wasn't that big of a deal.
A couple of things I have decided, I want to get the water flow better and I don't really want to deal with checking the exit ports all the time, and I think I want a perpetual system where I can harvest every 4 to 6 weeks. This means a new design so I have decided to build a cheaper version of the UC system where I'll have three 7.5 gallon square buckets in line with one 7.5 gallon control bucket. 2" pvc between the buckets and 3/4" pvc feeding the farthest bucket. One difference from the UC system that I'm going to "try" is instead of having an external pump(more expensive) pulling water from the farthest bucket back to the control bucket, I'm going to have a submersible pump push water to the farthest bucket. Basically just reversing the flow. I haven't thought of any reason why this would fail but I'm all ears ...
Ultimately, I would like to have three of these setups (three stages where I'm harvesting e plants every 4 weeks) in an 8x8 tent but for now I'll make just two and see if I can harvest 3 plants every 6 weeks.
BTW, I will be having a single reservoir that feeds all the control buckets with PH balanced water on float valves in the control buckets...
any, all thoughts and comments are appreciated... doesn't mean I have to listen to anyone };-)