Established, mature reef tanks typically have highly diverse microbial communities, while newer tanks, especially those started using dry rock, typically show much lower scores. Healthy reefs in nature show higher microbial diversity than degraded reefs. These comparisons support the conclusion that high microbial diversity is a positive feature, motivating many reefers to look for ways to increase diversity in their tanks.
In choosing a strategy, it’s worth considering the context to identify the likely reason for this score.
In new tanks, a low score probably indicates that typical community has not been established yet. Inoculation with live rock, live sand or live mud is a good solution in these cases.
In established tanks, a low score may result from the long-term use of sterilizing approaches (UV or Ozone). Unless required for managing known diseases, users may consider limiting their use temporarily so that free-living microbial populations can recover.
In any tanks where the microbial community is dominated by a single type (something microbiologists call a “bloom”), a low diversity score may result from the bloom. In these cases its better to focus on addressing the cause of the bloom (these are often associated with excess nutrients or disease outbreaks) rather than the diversity itself.
Many users ask whether bottled bacterial products are useful for increasing diversity. The difference between a low-diversity tank and a high-diversity tank is measured in the hundreds of different types, while bottled products contain only a few types. Based on these measurements and the long-standing observation that 99% of marine Bacteria cannot be cultured, we consider natural products to be a more effective approach.