Hydrocactus

Hydrocactus is a plant in Oxygen Not Included that functions as a natural water filter when it has access to Sand. When Sand is provided, Hydrocactus will act upon nearby water in the environment and perform filtration behavior, making it a biological option for water treatment within a base.

Hydrocactus is primarily valuable for its ability to interact with water and Sand to produce a filtering effect without requiring mechanical buildings or electrical input. This makes it useful in situations where duplicants need passive or low-maintenance water purification. The filtering interaction depends on the Hydrocactus having direct access to Sand; without Sand the plant does not perform the water-filtering function described.

• Provide a contiguous source of Sand adjacent to or within reach of Hydrocactus growth tiles so the plant can access the material it needs to filter water.
• Position Hydrocactus where contaminated or undesired water will come into contact with the plant’s influence; placing them along a flow path or near a collection area maximizes their passive filtering utility.
• Use Hydrocactus where low-maintenance, power-free filtration is preferred, for example in early base stages or in remote areas where building and powering mechanical filtration is impractical.
• Be aware that Hydrocactus requires Sand to perform its water-filtering role; maintaining Sand availability is necessary for continued filtration.

Hydrocactus provides a biological alternative to engineered water purification systems and integrates naturally into colony environments where Sand is available. Its role is limited to the filtration interaction described; other effects or resource outputs are not indicated in the referenced sources.