My pods are sterile so to speak, it is just that strain. No rock, no macro, all the tools and equipment is just for them and nothing else I even make up water just for the pods that way it wont get cross contamination with other types or bacteria. They are the bigger type pods more so than what you would normally get in your tank. I was tierd of buying pods as I keep a mandarin in a smaller tank I would not want to see it starve but love the fish and wanted to keep it fat and happy. I try to collect every week if I can and when I do everything goes nuts for it. As for how I do it I will put something together in just a min, it's not to hard just something you need to stay on top of. I have showed others but most seem to fail I think it's cause they tend to not keep things clean so the culture crashes. Oh as for my fuge I do have lots of pods in there but we all know you can never have to many when it comes to a mandarin plus like I said there bigger so it's more food for the bite LOL!!!