Max H2O Usage for Tank Sizing

I'm switching up from coco to rockwool and have space for around 1700 plants in 8" cubes on intermittent drip. I'm wondering if anyone can share what their max h2O usage per day is so I can make my tank bank is large enough. Thanks in advance and please let me know if I can provide more info.

read somewhere that it takes 2-2.5 gallons to flush the big momma 8x8x8. so if you ever wanted to flush the whole system at once you would need 4250 gallons.

not sure what you max daily usage would be once the plants are at their largest but i would guess somewhere around this is a good starting place.