Can the use of Nutrifix bio pellets reduce alkalinity?
Some minor depletion of alkalinity can be expected when using any form of bio pellet, as it is with all carbon/bacterially driven systems where bacteria are using up oxygen and giving off some Co2.
Most of the Co2 it is driven off via the skimmer, but there can be some depletion of the buffering capacity because of the increased Co2 generation. This will be more evident in systems with a high nitrate level as the growth of bacteria will be excelerated.
The suppression of alkalinity will be negligable once nutrient levels have fallen to trace levels. At this point, the growth of the bacteria is limited by the availability of No3/Po4 to more natural levels, consequently the Co2 generation drops off.