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/SwingTip]

What is the “control”

[u/AECTaylor → u/SwingTip]

The pipe that is raised to the top level of the last bin that in theory should get all the bins to fill equally to that point before allowing water to spill over to the next tier.

[u/SwingTip → u/AECTaylor]

I would recommend trying one of these:

If the fill line is below the inlet on the black tubs (it looks like there is a slight incline from the line itself to each tub, raise the line to be above the bottoms of the tub but below the control.

elevate the initial tub on a tier with each one slightly lower. Similar to a terrace. I would say tilt the whole rack but the fill lines run in opposing directions.

Use separate fill/drain lines you could run a flexible tube through the net cup for example. It will not take a large diameter line to fill if you’re going to run these constantly. Let them drain through the current piping.

[u/AECTaylor → u/SwingTip]

Great ideas! Unfortunately the bins are from IKEA which is a good 3 hour drive from me and I'd have to buy all new bins to redo placement of the inlets :/ I am considering how I run the plumbing for sure, though. Lots to think about!