One situation where I think bacterial additions may be a good idea is when you know that you have the wrong profile.
In particular, I'm referring to cyano. Once it gets well established, and especially when organic carbon dosing, it may very well be useful to add different species, assuming you can find a source that has bacteria in it that will thrive in your tank with your type of organic carbon added.
One potential way to do this is to get such additions from other reefers. I know that when I dose a lot of vinegar, I get lots of bacteria growing on my GAC that I periodically clean off. That white stuff (whether it is one species or hundreds of them) could easily be collected and might help seed a different aquarium that is having problems with cyano when dosing organic carbon.
In particular, I'm referring to cyano. Once it gets well established, and especially when organic carbon dosing, it may very well be useful to add different species, assuming you can find a source that has bacteria in it that will thrive in your tank with your type of organic carbon added.
One potential way to do this is to get such additions from other reefers. I know that when I dose a lot of vinegar, I get lots of bacteria growing on my GAC that I periodically clean off. That white stuff (whether it is one species or hundreds of them) could easily be collected and might help seed a different aquarium that is having problems with cyano when dosing organic carbon.