Coconut substrate opinions please

[Bogertophis]

...Does anyone have a brand that they haven't had an issue with? Or do you have this issue and have a solution? Or am I doomed to gnats? ...

Why not use those sticky fly traps that are just sticky stuff- nothing toxic. Read the fine print, I just did a quick search & found some (@ Walmart), but didn't read all the competing brands. Just one that's specifically for fruit flies & fungus gnats, indoor or outdoor use. I think it's not about the brand of substrate you use, but just being unlucky with pests waiting for your hospitality. And some nice moist substrate...