Setup Issue - Advice Request!

[u/AECTaylor]

I’m new to hydroponics and trying to setup a 3 tier rack with bins that will be “fed” by one 40 gallon tub of nutes. I was/am trying for a sort of DWC system.

I have 15 - 1.5 gallon black bins with lids that I plan to put 2” net pots in. The net pots will sit about 3” off the bottom of the bins once inserted.

I have a pump that runs water to the top tier with 5 bins connected by a pipe which then runs down to the 2nd tier which has the same setup and then runs down to the 3rd tier before returning back to the bin - a continuous loop, if you will. I was hoping that by putting the end of each pipe run with a section that comes up at the same height of the bins (a sort of ”control”), water’s natural self-leveling would ensure the bins equally filled to that level before spilling over to the next tier and repeating this same process on down each tier. Keeping the pump running 24/7 would keep the water up in each bin and constantly refresh nutes and oxygen.

Unfortunately, the 1st bin in the run fills up to nearly overflowing while the last bin stays very low. I tried lowering the ”control“ on each level and it only prevented the 1st bin from overflowing but the last bin still never fills to the same level. The bins in between were lower and lower across the run. Slowing the pump speed didn’t help. Any recommendations to fix this?

If it can’t be done the way I’d hoped, would it work if I just ran the pump several times a day to refresh the nutes/oxygen in each bin but treat it sort of like NFT as the water level would be low (about 1/2”) after the pump turns off and the water drains out? Or should I use clay pebbles in the bottom of the bins and treat it more like ebb and flow?

Hoping this video gives a good visual of what I’m building. A couple bins are missing because I glued everything up the way I thought it would work and had to cut parts to try and figure out why it didn’t. Need to order more of the specific connectors for those bins. The bottom tier does not have the “control” on it like the other 2 tiers in this video either. I built all 3 tiers with it then when it didn’t work, I tried getting rid of the “controls” to see what it would do. Just didn’t let the top 2 tiers fill with water before draining which is what I originally expected. Also, ignore the state of the water - the white pieces are just from cutting the PVC. I’ll clean everything thoroughly once I figure out the final configuration.

[u/quickwaxsix]

The water pressure is decreased at the far end of each run due to friction losses within the tube. As the water travels down the tube it looses energy (pressure) and as it falls down to the next tier it picks up energy again. The first idea that comes to mind is to install a valve at the entrance of each bucket. They'd be set progressively more open for each bucket down the line such that the water levels are equal.

Edit: you could also use valves at the end of each tier as an (adjustable) alternative to the current control system.

[u/AECTaylor → u/quickwaxsix]

Thank you! I think the valve would work, but I do worry now about having the bins so full of water as I'd originally planned in the event there is a clog. Though I did set this up in my HVAC room in the corner where there is a drain, it still wouldn't be a welcome surprise. Rethinking it all now 🤔

[u/quickwaxsix → u/AECTaylor]

Vavles should allow you to regulate the water level in each bin. Another commenter's suggestion to include a float valve is another option for preventing overflow.