You didn't say if the bottom of your res and the bottom of the plant buckets are at the same height or if the plant sites are elevated up on something raising them above the rez?
If your waterfall flow rate is low enough you will have no problems and all the buckets will maintain close enough to the same level. If your planning to crank up the flow on the waterfalls you will probably be backing up the 1" tubing and the level in the buckets will rise above the level in the rez (as it goes down)
You want big ass free flowing tubing if you want to really move water and not have issues.
That's why I stepped it up to 2" on my latest system - 250gph pump blasting through (4) 1/4" holes on each system an no air pumps anywhere
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