I am wondering if AISI-302 stainless steel parts are suited for permantent contact with the nutrients? It is because I am thinking about using a non return valve which in the reservoir which has AISI-302 grade parts. I don't know how aggressive the nutrients are to metals and if this kind of stainless steel might bleed toxic stuff into the reservoir.... Any idea? April 22, 2019 at 04:01PM Read more about this fix