Nah, those are nice assumptions but it doesn't work that way.
In our reef tanks we've created small, closed ecosystems and they rely on our skills as reef keepers to create some level of balance. Allowing our corals and fish to grow and be healthy. Mother nature has her hand in it but we've skewed her influence. And well we should because she can't handle it on her own.
Well, we need to remember the "balance" state of various bacteria populations in matured tanks should still be considered as "natural", as long as we do not pose a 'direct' influence to increase or decrease population levels of existing (target) organisms.
Adding probiotic bacteria is rarely problematic and most often beneficial. If you have any nitrates or phosphates that can be consumed by the bacteria it's going to happen in the water column long before any of the rock or media hosted bacteria will have any significant influence.
You're simply stepping on the gas pedal and burning more fuel until there's less fuel to burn and then your introduced bacteria perish. In that period of time they're breaking down and converting excess nutrients to food for your corals.
A correction here, with bacteria addition questions, I was assuming people plans to add bacteria directly to siporax section/container/reactor etc, so an overdose to a limited space.. I dont expect significant fluctiations/problems when its added to tank, either.
A few things to add, as far as I know, they will not consume only the nitrates and phosphates in water column, but contribute depletion of existing carbon sources, too.
Shouldn't we consider the feeding rights of siporax/rock/whateversurface hosted bacteria, then? In other words, we are temporarily reserve the living space and existing (all kind of) food sources to artificially added bacteria, which may be considered as a balance disruptor, to me.
If the bacteria on your rock were 100% effective at consuming all the excess from feeding you'd never have rock adsorbing phosphates, GHA growing while your test kit says 0 and cyano outbreaks.
Stacking the water column with a healthy population of the good guys is smart reef keeping.
A tiny question here, what people were doing before bottled good guys? 
Feeding fish and corals food that is only partially digested creates a peak in nutrient levels well above what the long term sustainable good guys can handle.
I am trying to figure out if you are advising periodical and frequent application of bacteria culture, or within long periods/emergency cases, like nitrate peaks etc..
Carbon dosing is beneficial because we're introducing food that allows the beneficial bacteria already in the system to populate at a level the tank wasn't supporting without an added carbon source. As the carbon is consumed nitrates and phosphates are also and we can bring those excess nutrients to a useful purpose while depleting them.
Continuing this process while your new Siporax or media of choice is populating isn't going to make that media effective any faster but it is going to offer the benefit of managing excess nutrients until it can pitch in.
