Why the Filter Splitter Matters
A Filter Splitter keeps one mixed belt from becoming a factory-wide cleanup job. It separates a selected item from everything else, but it only works smoothly when both output paths can keep moving.
The most important rule is simple: a blocked output can stop the whole splitter. That makes output handling—not just choosing the filter—the key to stable automation.
Alchemy Factory launched Version 1.0 on September 8, 2026. The available 1.0 notes do not publish a complete current specification table for automation devices, so verify the Filter Splitter’s name, ports, placement, and behavior in your current build before committing to a large layout.
| What to verify in-game | Why it matters |
|---|---|
| Selected filtered item | Determines which item is routed to the filtered exit |
| Splitter orientation | Changes how accessible each output is |
| Output belt destinations | Prevents either side from backing up |
| Device tooltip and live display | Best source for current-version behavior |
| Recent hotfix notes | May affect systems involved in the layout |
Community guides describe the Filter Splitter as a tool for separating one chosen item from a mixed-output belt. The selected item leaves through the filtered output, while all other items leave through the remaining output.
How Filtering and Outputs Work
Start by interacting with the splitter and choosing the item you want to separate. Community descriptions commonly call the filtered exit the highlighted or yellow output. Everything that does not match the chosen item uses the other output.
A useful mental model is that the device creates two responsibilities:
- The filtered lane must accept the selected item.
- The remaining-output lane must accept every byproduct.
- Neither lane can be treated as optional when the input belt keeps supplying items.
| Input item type | Expected destination |
|---|---|
| Selected filter item | Filtered or highlighted output |
| Any non-selected item | Remaining output |
| Items when one output is blocked | Splitter may stop moving items |
| Items when both output paths remain clear | Can continue through the intended routes |
The exact colors, port directions, and interface labels should be confirmed in your game. Guides refer to a yellow filtered output, but layouts can vary based on orientation.
One Steam community discussion adds an important edge case: players have used an unconfigured Filter Splitter as a bufferless multi-level splitter. That discussion is a player report, not a confirmed current design rule. Do not rely on a blank filter as part of a critical production line unless you test it in the live version first.
| Configuration state | Reported behavior or concern | Safe approach |
|---|---|---|
| Item selected | Selected item uses filtered output | Test with a small belt flow |
| No item selected | A player reported items can continue through | Verify in the current build |
| Filtered output blocked | All movement can halt | Give it a clear destination |
| Other output blocked | Filtered items can also halt | Consume, store, or discard byproducts |
Build a Stable Mixed-Output Line
The common example in player guides starts with rotten logs. These are described as producing planks and mushrooms together. A Filter Splitter can route mushrooms toward advanced fertilizer production while sending planks to another useful destination.
The specific machines and recipe details should be checked in Version 1.0, but the layout principle remains practical: separate the output immediately, then ensure both branches have somewhere reliable to send their items.
| Layout stage | Example purpose |
|---|---|
| Mixed-output source | Produces mushrooms and planks from rotten logs, according to community guides |
| Filter Splitter | Selects mushrooms as the filtered item |
| Filtered branch | Sends mushrooms toward an advanced fertilizer chain |
| Remaining branch | Sends planks to a consumer, storage, or disposal route |
| Overflow handling | Keeps the plank branch from stopping the splitter |
Keep the branches physically distinct when testing. One community guide specifically advises against feeding both outputs back into the same belt, because it becomes harder to see whether the filter is doing the work you intended.
A safe first version uses storage at the end of each branch. Storage gives you time to confirm that the selected item reaches the correct lane and that the byproduct lane is not silently filling.
After that, replace temporary storage with real consumers where appropriate. Player guides suggest several possible uses for planks, including fuel-related processing, storage, or trash. Use only destinations available in your current save and version.
Prevent Belt Lockups Before They Start
The classic failure is focusing entirely on the filtered item. You may successfully send mushrooms where they need to go, while planks accumulate unnoticed. Once the plank side backs up, guides report that mushroom movement stops too.
Build with the unwanted or lower-priority output in mind first. If it has a stable destination, the filtered branch is far less likely to stall during a long run.
| Byproduct strategy | Benefit | Watch for |
|---|---|---|
| Consume it in another chain | Turns byproducts into useful input | Downstream machine can still fill |
| Send it to storage | Makes testing and inspection easier | Storage eventually reaches capacity |
| Use an overflow route | Protects the main line from excess output | Confirm the route accepts the item |
| Send it to disposal | Avoids accumulation | Loses the byproduct |
Before leaving a new line unattended, check these points:
- Confirm the filter is set to the intended item.
- Watch both outputs until several items have passed through.
- Check that each branch has moving belts and a valid destination.
- Inspect any storage or overflow point for accumulation.
- Recheck the line after changing downstream production.
- Test orientation before building around vertical or hard-to-reach outputs.
Some guides recommend rotating the splitter with the T key and using lab stands or lifts to reach vertical outputs. Treat those controls and placement options as version-sensitive guidance: verify them in your current interface.
Using the Splitter for Fertilizer Production
Community sources consistently connect the Filter Splitter with advanced fertilizer automation. Their example is to separate mushrooms from planks after processing rotten logs, then send mushrooms to an assembler together with basic fertilizer.
The available current-version reference does not confirm complete recipes, rates, unlock levels, or production values. Avoid planning around older numerical claims such as growth multipliers, device dimensions, or exact nursery ratios.
What is useful from the example is the logistics lesson: advanced production chains often depend on a single item from a mixed stream. The splitter gives that item a dedicated path while keeping the rest from contaminating the route.
| Goal | Suggested routing concept |
|---|---|
| Collect mushrooms | Select mushrooms in the Filter Splitter |
| Continue fertilizer production | Route the filtered branch to the relevant current-build machine |
| Handle planks | Route the remaining branch to a valid consumer, buffer, or disposal path |
| Avoid a full stop | Keep both branches clear at all times |
| Troubleshoot poor output | Inspect branch capacity before changing the filter |
If the filtered item is not leaving through the port you expected, stop the input belt and inspect the splitter’s direction. Then test again with a storage box or another visible endpoint. This is faster than rebuilding an entire production floor around an incorrect orientation.
FAQ
What does an alchemy factory filter splitter do?
An alchemy factory filter splitter separates a selected item from a mixed belt. Community guides describe the selected item leaving through the filtered output, while all other items use the remaining output.
Why did my Filter Splitter stop?
One of the output paths may be blocked. Player guides report that if either the filtered branch or the remaining-output branch backs up, the splitter can stop moving all items.
Which output carries the filtered item?
Community guides refer to the highlighted or yellow output as the filtered exit. Confirm the port indicator and device orientation in your current build.
Can I ignore the non-filtered output?
No. Even if the filtered item is your priority, the remaining items still need a destination. Use a current-build consumer, storage, overflow route, or disposal method so that branch does not fill.
Should I trust older splitter statistics and unlock details?
No. The current 1.0 reference advises using the live build menu, tooltip, and production display as the authority because complete current automation specifications are not published in the available patch notes.