We suggest that you keep whatever your growing practices currently are. Also, we suggest that you add BUD BIONICS. BUD BIONICS circulates nutrients very productively, that decreases nutrient sorption response from happening. Some of our farmers using BUD BIONICS have told us that their tanks have lasted up to 12 days before changing the tank. You as farmers will have to make that determination. We could easily perceive that adding BUD BIONICS to your tank would extend length of time for the need to change your tank allowing perhaps greater than 12 days. Keep in mind that all farmers grow differently.