General procedures for design, setup, and operation of Holobiont-style tanks
3.1 System Design
Why Overflow Is Required
In this system, bacterial populations explode, resulting in incomparably higher oxygen demand than conventional tanks. The suitability of each filtration method is shown below.
Filtration Type
Sludge Transport
Oxygen Supply
Suitability
Overflow
Auto-falls to sump
Splash aeration sufficient
Only suitable (◎)
Canister filter
Clogs immediately inside
Pump circulation only
Not suitable (×)
HOB filter
Trapped by wool/media
—
Not viable
Undergravel filter
Accumulates in substrate
—
Not viable
Sponge / box filter
Trapped by sponge
—
Not viable
In this system, massive proliferation of heterotrophic bacteria raises oxygen demand significantly above normal tanks. Additionally, the structure must reliably transport generated biomass (sludge) to the sump, making overflow the essential design.
3.2 Setup Procedure (~1 Month)
1
Substrate Selection
Select a porous substrate that does not disintegrate underwater. Large surface area for bacterial colonization and low nutrient content are desirable. The chemical properties of the substrate determine the pH lock equilibrium point, so choose according to target water quality.
2
Filling the Sump with Porous Media
Fill the sump with as much porous media as possible. Keep it separated from the pump compartment. The goal is to maximize bacterial colonization surface area.
3
Dry Run + Initial Dosing
Fill with water and run the overflow empty. Begin ghost feeding (adding small amounts of food as an ammonia source) and carbon source extract dosing. Cloudiness begins within days.
⚠ Prohibited During Setup Water changes and water clarifiers Cloudiness is a bacterial bloom indicating the system is progressing normally. Intervention resets heterotrophic bacterial colony formation.
4
Continue 1 Month → Sudden Clearing
Continue daily dosing through the cloudiness. After approximately one month, rapid water clearing is observed. This indicates that bacterial floc formation and substrate colonization are complete, and the system has transitioned to a stable state. Theoretically, ammonia assimilation by heterotrophic bacteria is established once sufficient oxygen and carbon sources are secured, making livestock introduction possible from this stage.
5
Plant Aquatic Plants & Introduce Detritivores
After confirming clearing, plant aquatic plants and introduce detritivores to the sump. If adopting the full-auto method described in Chapter 2, select organisms small enough to pass through the pump.
6
Gradual Fish Introduction
Introduce in order: bottom-dwellers → mid-level → upper-level → apex predators. Feed normally until detritivores stabilize. Once detritivores flow in through the pump and fish are observed naturally preying on them, feeding can be gradually reduced.
3.3 Management Procedures
Daily Management
Management after system stabilization is extremely simple.
DailyDose carbon source extract
DailyObserve tank (check for abnormalities)
As neededTop off evaporated water
As neededTrim aquatic plants
When planting aquatic plants, supplementation of trace elements such as potassium, magnesium, and iron is required. Consider adding them to the carbon source extract or using liquid fertilizer for aquatic plants.
Troubleshooting
The advantage of the aerobic approach is that abnormalities are visually identifiable. Address the following signs when observed.
