Thermodynamics · Fluid Stratification
Update #3 (v0.5.6) fundamentally overhauled Sandustry fluid physics by raising Lava density to 200. This created natural liquid stratification: Water (density 100) and Florinol (~120) now float buoyant on Lava pools, causing legacy launcherless pump intakes to ingest the wrong fluid or trigger rapid Scoria freezing. Master multi-depth intake pumping, Basalt thermal buffers, and native Advanced Filter Wall rotation to keep fluid networks fully automated.
Quick answer
In Update #3 (v0.5.6), Lava density increased to 200, causing Water (density 100) and Florinol (~120) to float directly on top of Lava pools. Pumps placed near the surface of a mixed pool will draw floating water instead of Lava, or trigger rapid Scoria freezing that chokes the intake. To pump pure Lava, position your Pump intake at the floor of the basin, line walls with inert Basalt, and use vertical Advanced Filter Walls (press 'R' to rotate) to separate fluid layers.
01
In Update #3 (v0.5.6), the physics simulation received a game-changing update: molten Lava density was increased to 200. This shifted all multi-fluid interactions across the desert.
Previously, fluids mixed or displaced each other erratically. Now, fluids naturally stratify according to strict physical density: dense Lava (200) rests at the lowest basin floor, Florinol (~120) floats above Lava, and Water (100) floats on top of both, while Steam and Florin Gas rise into the atmosphere.
| Fluid / State | Density Value | Natural Layer | Thermal Interaction |
|---|---|---|---|
| Steam / Florin Gas | 0 | Atmospheric Layer | Rises buoyant; captured by ceiling Condensers |
| Water | 100 | Upper Surface Layer | Floats on Florinol & Lava; flashes to Steam on Lava contact |
| Florinol | ~120 | Middle Strata | Floats on Lava, sinks in Water; fuels Florinol Batteries |
| Stratacore Chunks | ~130 | Buoyant Solid | Floats upward through Lava shafts (Lava Elevator) |
| Lava | 200 | Lowest Basin Floor | Melts natural rock; freezes to Scoria with cold buffers |
| Solid Gold | 19300 | Bedrock Sinker | Sinks rapidly through all known liquids and sand |
02
Legacy launcherless pumping designs failed in Update #3 because pumps mounted at the fluid surface now pull floating Water or Florinol rather than Lava. To pump pure Lava, the Pump intake tile must be submerged directly into the bottom stratum.
Always encase your Lava basin in Basalt or Foundation blocks. Because Lava destroys Fluxite and Redsoil on contact, an uncontained basin will erode downward, causing the fluid level to drop below the pump intake.
03
Many players mistakenly search for a 'Advanced Filter Wall mod', unaware that vertical fluid filtering is a native feature in Sandustry. When placing any Filter or Advanced Filter, press the 'R' key to rotate the bounding box 90 degrees into a vertical Advanced Filter Wall.
By setting a lower Advanced Filter Wall to allow only Lava and an upper Advanced Filter Wall to allow Water, you create an unpowered gravity weir. Fluid stratifies naturally, and each layer exits into its own dedicated pipe manifold with zero cross-contamination.
04
Direct surface contact between Water and Lava triggers violent steam bursts and can solidify Lava into Scoria crusts. If a crust forms over a pump intake, the entire fluid circuit stalls.
Place a 2-tile Basalt baffle between your condensation rain catchers and deep Lava storage. This allows excess Water to overflow into a drainage channel before it can interact with the molten reservoir.
Questions answered
Update #3 increased Lava's physical density to 200, while Water has a density of 100. Due to granular fluid buoyancy simulation, lighter fluids naturally float on heavier fluids, creating distinct layers in any multi-fluid chamber.
If your pump was placed near the top of an open pit, rain or condensation created a layer of floating Water. The pump either ingested water or solid Scoria formed over the nozzle. Move the pump to the bottom of the basin encased in Basalt.
Because Lava has a density of 200 while Water (100) and Florinol (~120) are lighter, lighter liquids float on top of Lava. To prevent the pump from ingesting water or creating crust jams, submerge the Pump intake directly at the bottom tile of the basin, enclose the reservoir walls in inert Basalt, and use vertical Advanced Filter Walls to block floating surface fluids.
Equip the Filter or Advanced Filter from your inventory, hover over the target tile, and press the 'R' key to rotate the filter from horizontal to vertical Wall orientation. It allows you to create vertical fluid gates.
Yes. Advanced Filter Walls allow multi-element configuration, letting you permit multiple fluid or solid types on a single wall without cascading separate single-rule filters.
Build a stepped settling weir. Because Lava (200) sinks, Florinol (120) sits in the middle, and Water (100) floats at the top, arrange three output ports at differing heights: bottom port for Lava, mid-level port for Florinol, and top spillway for Water.
Evidence notes
These are useful player examples, not official specifications.
