As I've said before I'm skeptical of the commercial pond bacteria too. I think a lot of the credit that bacteria gets should be given to using diffusers to keep the bottom aerobic so the bacteria that is naturally present will work.

All I see out there is anecdotal evidence. No credible scientific studies complete with controls, i.e., similar ponds in similar conditions side by side complete with a control pond.

I bought some once. Appeared to be mostly sawdust. I found that rather suspicious.

If pigs could fly bacon would be harder to come by and there would be a lot of damaged trees.