No Man's Sky: How to Make Units with Chlorine Expansion

In No Man's Sky, Chlorine expansion is an early-game method for generating large sums of units by multiplying Chlorine inside a refiner. Placing one part Chlorine and two parts Oxygen into a Medium or Large Refiner produces six parts Chlorine. By running this loop repeatedly and expanding your Oxygen supply, you can fill your inventory with high-value stacks of Chlorine to sell at space stations.

Essential Blueprints and Materials

To run the expansion loop, you need equipment capable of accepting two simultaneous inputs. A Portable Refiner cannot perform this recipe because it only has one input slot.

1. Medium Refiner Blueprint: Purchase this blueprint from the Construction Research Station aboard the Space Anomaly. Medium Refiners do not consume Carbon fuel and can process two ingredients at once.
2. Refiner Crafting Components: Gather Magnetised Ferrite (refined from Pure Ferrite) and Microprocessors (crafted or purchased from trade terminals) to construct your refiners.
3. Starter Chlorine: Refine Salt collected from underwater minerals or flora into Chlorine, or purchase a starting batch directly from NPC starship pilots at a space station.
4. Oxygen: Gather Oxygen initially from hazardous flora or trade terminals before setting up automated extraction.

Building two or more Medium Refiners in your base allows you to run multiple stacks in parallel, cutting down the total refining time.

Setting Up an Automated Oxygen Farm

While you can buy Oxygen from pilots or terminals, automated extraction removes all overhead costs and sustains continuous refining.

• Locate a Hotspot: Install the Survey Device upgrade on your Multi-Tool and scan planet surfaces to find a concentrated Oxygen gas hotspot.
• Deploy Extractors: Build Gas Extractors over the hotspot and connect them with Supply Pipes.
• Add Storage: Chain the extractors to a cluster of Supply Depots to stockpile Oxygen while you are away.
• Power the Site: Power the extraction network using Solar Panels wired to Batteries, or connect to an Electromagnetic Generator if a power hotspot is nearby.

Emptying these depots provides tens of thousands of Oxygen units, allowing you to feed multiple refiners without spending units on raw materials.

How to Execute the Chlorine Expansion Loop

Once your base refiners and starting supplies are ready, follow these steps to multiply your stock:

1. Place your starter Chlorine into the top input slot of a Medium Refiner.
2. Place Oxygen into the secondary input slot.
3. Verify that the output recipe displays Chlorine at a 1:2 to 6 conversion ratio.
4. Start the refiner and let it process until the output slot fills.
5. Take the refined Chlorine from the output hopper and split it, placing a portion back into the top input slot to continue the cycle.
6. Transfer the surplus Chlorine into adjacent refiners or your cargo hold.

Always store a backup stack of Chlorine in a base storage container. If you accidentally sell your entire inventory, you will need to locate Salt or buy more Chlorine to restart the process.

Where to Sell Chlorine for Maximum Profit

Selling massive amounts of Chlorine at a galactic trade terminal will flood that star system's market, crashing the local demand and sharply reducing the price for future sales.

• Sell to Visiting Pilots: Trade your Chlorine directly to NPC pilots landing inside space station hangars. Transactions with individual pilots do not depress the station's trade terminal pricing.
• Warp After Terminal Sales: If you choose to sell at a galactic trade terminal, sell your entire stock in a single transaction, then warp to a new star system before liquidating your next batch.

Use your initial profits to buy inventory slots for your Exosuit and starship cargo holds. Expanding your carrying capacity allows you to transport larger hauls per trip and accelerates your progression toward buying high-tier ships and freighters.