I am making the switch from soil to hydro with a 18 gallon rubbermaid tub 6 plant DWC system. I think I have everything down I am just still pretty confused regarding changing the reservoir. I will be using the 3 part fox farm nutrients and following their hydro schedule. From what I understand you need to change the reservoir (the nutrient solution) every ~2 weeks to prevent nutrient imbalances in the solution (which would cause nutrient lockouts). So you dump out all the nutrient solution down the drain, and fill it with new solution. My questions are: 1) Switching the nutrient solutions every 2 weeks with an 18 gallon reservoir seems like it would become realllly expensive on nutrients (~1-2tsp per gallon on the schedule thats like a fourth of the bottle or close enough lol), what is the input on this? 2) When switching the solution out with a fresh solution, how long can the roots stay out of solution for (being out in the air) ? 3) Hypothetically speaking, say it is week 3 of flowering (first week out of two till the next reservoir change), you put the normal required amount of nutrients to the specific ppm/EC, then during the week 4 ( two week out of two till reservoir change) do you just add a solution of the required ppm/EC back to the reservoir as it drops? I appreciate any and all help! Sorry if some of this is blurry I am stoned right now! Thanks!