I wont run less than 200gph but perfer 400 for 30 gallons of water in a single tote. My buckets are getting 1/6th that and being fed with 5ft of plumbing. Not alot of water movement in the buckets. The plants dont mind though, roots look good. If I had it my way each bucket would get 200gph direct with a venturi with my main res getting 400gph. Atm i bet my totes are getting about 50gph.

I would suggest too high of flow in the rest could mess with nutrient retention time at the root zone, if thats a thing. I know ive seen high fert methods on here not work as well during flower. What is that phosphate?