An alternative to flare stacks and voiding. The Fluid Memory Unit stores an unlimited amount of a single liquid or gas in one building, at one temperature. The more it holds, the more power it draws — storage is cheap to build and expensive to hoard.

Mine a loaded unit and it packs itself into an item carrying its contents and their temperature. Place that item and everything comes back.

What this fork is, and what it will never be

A holding pattern, not a takeover. The original has no Factorio 2.1 release — and 2.1 deleted the fluid API it was written against, so it cannot simply be flagged compatible — plus a fluid duplication bug and a bug where a drained unit never unpacks. This is those things fixed and nothing else.

The scope, stated as a promise:

• ✅ Factorio 2.1 support
• ✅ Bug fixes
• ❌ No new features
• ❌ No balance changes — same recipe, same technology, same power curve, same 120k buffer
• ❌ No redesign, no "improvements", no opinions about how the mod should work

It retires the moment notnotmelon publishes a 2.1 release. It gets marked deprecated and points back at the original, and you should switch. Because the prototype names are unchanged, switching either way is just swapping the mod — your existing units keep their contents.

This is a continuation fork

The original Fluid Memory Storage is by notnotmelon (Zachary Picco), released under the MIT license. All of the design, the code, and the artwork are his work. Source: **https://github.com/notnotmelon/fluid-memory-storage**

The last release was 1.7.9 in August 2025, and there is no Factorio 2.1 build. This fork exists to fill that gap and to fix the bugs listed below, nothing more. It is not endorsed by, affiliated with, or connected to the original author — he has not been asked, and this is not his work being represented as maintained.

If notnotmelon ships a 2.1 release, this fork retires. It will be marked deprecated and point back at the original. Take the original when that happens.

The duplication fix is adapted from Upsidedownfoxxo's deep-storage-unit-se-fox, also MIT — an item-side fork of the sibling mod, where the same fix has been running since October 2025.

What changed

Runs on Factorio 2.1. 2.1 removed the fluid box API this mod was built on — LuaEntity.fluidbox is gone and everything moved onto the entity itself — so every fluid read, write, filter and extraction had to be ported. This is the larger half of the work and the part most worth reporting bugs about.

Fluid duplication is fixed. A fluid-memory-unit ghost no longer carries stored contents, which is what made the exploit possible: anything that satisfied the ghost with an ordinary empty unit — a blueprint, an undo, a super-force-build, construction robots, a repair turret — restored the fluid into the new unit while the packed item stayed in your inventory. Closes #15.

The trade-off: blueprinting or undoing a loaded unit no longer carries its contents to the rebuilt unit — bots will build an empty one. Nothing is lost. The fluid is still in the packed item in your inventory, and placing that item by hand restores it exactly as before. That workflow is gone deliberately: it is the same code path the exploit used.

A drained unit unpacks as a normal unit again. Fluid amounts are floating point, so an "empty" unit still held something like a billionth of a unit of fluid, and only exactly zero counted as empty — so it stayed packed forever and could never be reused for another fluid. Anything under 0.001 now counts as empty. Closes #14.

Fluid overlays no longer stack. The tinted overlay was redrawn on every build, clone, filter change and fluid migration without removing the previous one, so they piled up and the colour drifted.

Crash fixes. Mining, destroying, deconstructing or cloning a unit the mod had lost track of used to throw an unrecoverable error and take the save with it. Separately, cloning a unit whose hidden power entity was already gone tried to create a prototype belonging to the item mod — an outright crash for anyone running this mod without Memory Storage installed.

No balance changes. Same recipe, same technology, same power curve, same 120k buffer. This is a bugfix set.

Full detail, including what is not fixed: see the FAQ tab.

Switching from the original: nothing to do

Just swap the mods. Disable Fluid Memory Storage, enable this, load your save. Your units keep working and keep their contents - the unlimited amount held behind the tank, at the right temperature.

That is worth spelling out, because it is not automatic for a fork in general. A Factorio mod's saved data is keyed to its internal mod name, and a fork has a different internal name - so a fork normally starts out knowing nothing about the units already in your factory, leaving them as dead boxes with a blank window.

This mod recovers them. Each unit publishes its total to a hidden constant combinator so the circuit network can read it, and a combinator is part of the world rather than mod data - so on first load the fork finds every unit it does not recognise, reads that signal back, and restores the stored amount. Temperature is read from the fluid still in the tank. It reports in chat how many units it adopted and how much was restored.

Switching back to the original works the same way. Take a backup first regardless - it costs nothing and this is your factory.

One case it cannot cover: a unit whose tank is completely dry has no fluid to read a temperature from, so its stored temperature is set by the next fluid that enters it. The amount is still restored in full, and the mod says in chat when this happened.

Compatibility

• Do not run this alongside the original. Both define the same prototypes; the mod list declares them incompatible so Factorio tells you clearly instead of failing with a confusing error.
• Existing saves work, contents and temperature included - see "Switching from the original" above.
• Multiplayer: every player needs the same version, as with any mod.
• The item sibling is Memory Storage (Continued), which has the same fixes on the item side. Either mod runs fine on its own.

Reporting bugs

Bugs in this fork go to https://github.com/restjack/fluid-memory-storage/issues. Please do not report them on notnotmelon's tracker — he did not ship this build. Bear down especially hard on anything involving fluid temperature, filters or capacity: those code paths were rewritten for 2.1 and have had the least real play time.