Answer: It's best to go to your local certifying board and request a laundry list of items that they deem acceptable. Each certifying board may approach this differently. The best bet is to be proactive, bringing them our data sheet for Dura-Skrim 20WW (fish and shrimp safe). Please visit our Aquaponics page for more information.
Unlike organic farming your system is based on soil-less growing conditions and the rules and regulations for organic certifications are based on traditional farming. You will want to use plastics that are fish safe. If the plastic is potable water safe, then that is even better.