Not too long after we released our flagship product PNS ProBio™ (a live culture of purple non-sulfur bacteria) in 2018, we introduced its companion product PNS YelloSno™ (a food for corals and other filter-feeding invertebrates). While more than a few coral foods had just entered the market around that time, PNS YelloSno is markedly different. Thus, we’ve gotten a lot of inquiries about it over the last couple of years. And still get a lot of questions! Thus, we here present a short article describing the content and suggested use of this unusual product.