At Sydney Zoo, we were asked to develop an evidence-based microbial strategy to manage recurring summer algal blooms across an interconnected moat system of approximately 12 million litres — receiving continuous nutrient input from animal waste and uneaten feed.
Six weeks after our first onsite investigation, and under peak summer conditions (high temperature, strong sunlight), water quality would normally be expected to deteriorate further.
Instead, after Sydney Zoo staff commenced beneficial bacteria dosing on 24 December 2025, a clear improvement in water clarity was observed within approximately 2.5 weeks.
One particularly encouraging outcome was the performance of the bottom dam — the final collection point supplying the entire moat system. Despite receiving a very high nutrient load and operating without any installed aeration system, the water remained clear, with no green water or cyanobacterial blooms observed.
This project reinforced an important principle: sustainable water quality improvement comes from nutrient control, microbial competition, and ecosystem balance, not short-term chemical suppression. Continue Reading...
