# Beneficial-microbe reservoir

> A beneficial-microbe reservoir deliberately inoculates hydroponic solution with helpful bacteria and fungi so they occupy the root zone before pathogens can; GenetixBay prefers this approach.

- Canonical: https://genetixbay.com/knowledge/glossary/beneficial-microbe-reservoir.html
- Also written: bio reservoir, biological reservoir, beneficial reservoir, microbe-dosed reservoir, living reservoir, bio-buckets
- Glossary category: Systems and media · Evidence: Supported
- Status: Draft: awaiting expert review · Updated: 2026-10-31
- Licence: CC BY-SA 4.0 (https://creativecommons.org/licenses/by-sa/4.0/), attribute "GenetixBay cannabis glossary"

A beneficial-microbe reservoir is a hydroponic strategy in which the solution is regularly dosed with live, beneficial organisms, typically *Bacillus* species, sometimes *Trichoderma* or mixed consortia, and is kept free of sanitisers that would kill them. The [beneficials](https://genetixbay.com/knowledge/glossary/biological-control.md) colonise roots and surfaces, compete with pathogens such as *[Pythium](https://genetixbay.com/knowledge/glossary/pythium.md)* for space and nutrients, and can form a protective biofilm on healthy white roots.

## In practice

Dose according to the product, usually weekly or with every reservoir change, and avoid chlorine, [peroxide](https://genetixbay.com/knowledge/glossary/hydrogen-peroxide.md) and other oxidisers that wipe them out. Keep the solution cool (about 18-21 °C, 64-70 °F) and well aerated; beneficials do not replace good temperature and oxygen management. Roots in a healthy bio reservoir are often tan-tinged or slightly fuzzy-white; slime and a sour smell indicate trouble.

## Myth check

House position: a beneficial-microbe reservoir is preferred. Bacteria will show up in any reservoir regardless, so you may as well have the good ones. A [sterile reservoir](https://genetixbay.com/knowledge/glossary/sterile-reservoir.md) is valid too, but you must commit to it fully; it's a personal choice. Evidence: Supported for biological control of root pathogens in hydroponics; product results vary. See [root rot and Pythium](https://genetixbay.com/knowledge/diseases/root-rot-pythium.md).

## Don't confuse with

- **Sterile reservoir**: the opposite strategy.
- **Compost tea**: a brewed soil drench, not a hydro inoculant.

## Related terms

[Sterile reservoir](https://genetixbay.com/knowledge/glossary/sterile-reservoir.md), [Reservoir](https://genetixbay.com/knowledge/glossary/reservoir.md), [Root rot](https://genetixbay.com/knowledge/glossary/root-rot.md), [Dissolved oxygen](https://genetixbay.com/knowledge/glossary/dissolved-oxygen.md), [Compost tea](https://genetixbay.com/knowledge/glossary/compost-tea.md)

## Read more

- [Root rot and Pythium in cannabis](https://genetixbay.com/knowledge/diseases/root-rot-pythium.md)
- [Recirculating deep water culture (RDWC)](https://genetixbay.com/knowledge/systems/rdwc.md)

## Sources

1. Colorado State University Extension PlantTalk 2043. Root disease problems and management in hydroponic systems. https://planttalk.colostate.edu/topics/miscellaneous/2043-root-disease-problems-management-hydroponic-systems/
2. Punja ZK, Rodriguez G., 2018. Fusarium and Pythium species infecting roots of hydroponically grown marijuana (Cannabis sativa L.) plants. Canadian Journal of Plant Pathology 40(4):498-513. https://doi.org/10.1080/07060661.2018.1535466