Ive used it for marine [i dont do FW, but can give good advise on cycling, etc.] and it worked but it all depends on how it was shipped. Sometimes, a batch has gone bad because it wasnt kept at the right temp during shipping.
Its the only bacteria additive that even makes sense! 1. It has to be kept cold so the dormant bacteria dont wake up and have nothing to eat and starve/suffocate to death. 2. It doesnt just sit on a shelf immortally. 3. There IS a difference between the marine and FW bacteria! Thats why FW dips for SW ich makes the parasite die, because it lives in SW. So all the other products that say for FW and SW dont even make sense. IMO, they are just added slime that the fish dont need, and if overdosed can cause difficulty breathing because it coats their gills as well as adding slime coat to the rest of the body.