I've posted part of this idea on another thread and posting it here to spark further discussion of this idea of mine.
I'm currently using 300ml of NPBP in my system, but NPBP aren't the best bacteria housing media, simply because bacteria can only colonize the surface area and I don't think the pellets are that porous.
And unlike vodka dosing, most of the bacteria should only colonize the surface of the pellets as it's where they'll get their food.
So in order to boost the bacteria housing capabilities of the NPBP, I propose of using another media that's more porous than the pellets, in this case, I proposed the use of sugar grain sized coral sand.
The reason why I chose this media is because of the grow of carbon source utilizing bacteria is very fast, in the ZEOvit system, users need to pump the ZEOvit reactor everyday to dislodge some bacteria so that it won't clog up all the surface area of the zeolite media.
In the case of NPBP, the addition of coral sand to the NPBP reactor will probably allow a greater number of bacteria to be housed in the reactor, similar to the black-n-white ball denitrators.
However we may still have the similar problem that zeolite had - bacteria growth clogging all the surface area of the media. In the case of coral sand inside a NPBP reactor, the constant movement may help to dislodge some bacteria, furthermore, it may be possible that the bacteria could alter the local environment such that the pH is lowered and thus the coral sand may slowly dissolve. Eventually more coral sand will need to be added to the reactor, and this will eliminate the need to use a zeolite reactor for the daily pumps.
So to test my theory, I just added some 50-100g of fine grain coral sand into my reactor, it may boost the bacteria housing capability of my NPBP reactor by a few folds, who knows ;p