Definitely sterile. I got back into growing after a 20 year hiatus and I started with bennies. After that first grow, I switched to sterile and have no regrets. A system with bennies requires way too many bottle of this and that. Sterile cuts it down to your base nutes, some cal-mag and something to keep things clean like 29 percent H202, Southern AG, pool shock etc. If you don't use bennies or a sterile system, you're going to have nothing but issues.