PSB vs BB question

Recently I've suddenly received a lot of this same question regarding: can I put PSB and also BB together? or I've bought PSB do I still need BB?

First of all you shouldn't be using PSB or BB product but given us asians we love maximizing our tank and tends to overload it.

If you're lazy to read all the technical stuff just scroll down to conclusion

ok now Lets break down everything and I'll explain them thoroughly.

BB stands for beneficial bacteria, meaning any bacteria that are involved in the nitrogen cycle will be classified under beneficial bacteria.

Nitrogen cycle

Nitrification - Aerobic - Oxygen environment :
Ammonium (NH4) convert to Nitrite (NO2) and finally nitrate (NO3). This is phase 1 of the nitrogen cycle done by the usual nitro bacteria. This will be the typical phase achievable by the common aquarium, the remaining NO3 will be removed by water change or by plant. Energy involved oxygen.

Denitrification - Anaerobic - very low to zero oxygen environment :
In phase 2 we will see the completion of the nitrogen cycle where nitrate (NO3) convert back to Nitrite (NO2) convert to nitrite oxide (NO)  convert to nitrous oxide (N20) and finally to Nitrogen gas (N2). The bacteria responsible for the denitrification process typically involve the bacillus species and also PSB. Energy involved is organic carbon.
                                           
So there are 2 phases in the nitrogen cycle, and phase 2 is almost impossible to achieve in the typical aquarium environment because of the lack of the organic carbon.

BB is usually referred to the nitro bacteria in phase 1 when PSB also falls under BB. The differences with BB and PSB is that BB as in the chart above thrive in oxygen environment and PSB thrive in low oxygen environment.

Conclusion
It is therefore essential that BB referring to the nitro bacteria compliments with PSB in the low oxygen environment because in your tank you will have high oxygen area and also low oxygen area (example in the substrate). Then you've cover both this area which in my opinion the low oxygen area is the red zone, danger zone. Food particle falls or gets trapped in the low oxygen area will easily get fungus and breed nasty bacteria if without PSB.

So there you go, PSB and BB should be use together, but better still, lower your bioload by reducing fish or increasing your tank size and forget about this 2 product.

added noted: Many commercial brand claims they have nitrification bacteria in a liquid bottle, as you now know, nitrification occurs in aerobic environment and they use oxygen as energy source. Logically non will survive in a liquid sealed bottle. Only get your BB or nitrification bacteria in endospore stage. Endospore is when the bacteria is in the dormant stage that waits for nitrogen and carbon and they'll spring to life. In this stage they will not die even when there are no oxygen and no food.

PSB on the other hand can use light as energy source to survive even without oxygen, so they will survive in a sealed bottle provided they have accessed to light. This is the reason PSB bottle are always translucent to allow lights to passed through.