The Drop Tank is a very unique structure that is mainly used to allow iridium to flow only one-way. It is sometimes used with Spawn Points, so costly purchases, such as upgrades, don't deplete the iridium stored in the Spawn Station's tank. However, this is not commonly used, as a Distributor paired up with a Distributor Cap are more effective for this; partially because the Distributor is given maximum priority in piping systems.

The Drop Tank also works in a special way. It has an input and an output, with the output being the bottom pipe opening. When iridium is supplied from the top, the top tank begins to fill. When filled, the bottom tank begins to fill. When this is filled, iridium is basically passed through the Drop Tank. Both of these tanks have a capacity of 320 iridium, and therefore it takes a long time to fill both of them and allow for a normal iridium flow. However, if iridium is taken by the bottom pipe, the bottom tank will deplete, however it will not affect the top one. If iridium is taken by the top pipe, the top tank depletes but doesn't affect the bottom tank. The top tank also can't be refilled by the bottom pipe. These properties make it useful for one-way iridium flow management.

Another interesting property of the Drop Tank is that while it is placed as one piece, the top and bottom halves are separate structures, meaning that they can be destroyed separately, leaving the player with a normal-functioning tank.

Pros and Cons


  • Allows for one-way iridium flow
  • Small and compact
  • Stores a lot of iridium
  • Allows to create efficient, small and compact tanks of the top half is destroyed


  • Expensive
  • Due to the top pipe opening, it is hard to do piping with it
  • Takes long to fill
  • A Distributor is better for one-way iridium flow
Pipes PipeT-JunctionFour-WayElbow
Extractors Well PumpCondenserSubmersibleCrystal Resonator
Tanks Small TankStandard TankLarge TankReservoir
Special CapDistributor CapRefill StationValveDrop Tank
SeatBridgeStarter Turret
Defense WallKeepGate
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