Once a fountain has been activated, vaccing up some water from it will grant the ancient water effect. The water tank HUD will become sparkly and flash in rainbow colours, and the water tank's stack number is replaced with a timer counting down from 29 seconds. In this time the vacpack's water supply is unlimited, and the water blobs have a subtle rainbow sheen which leave sparkly particles when it comes into contact with a surface or a slime. When the effect wears off, it will leave the water tank with normal water at maximum capacity.
- You are required to have the Water Tank upgrade to vac up the water to activate the Ancient Water effect.
- For convenience, it may be an idea to have a teleporter based near a fountain and using it to instantly replenish your water supply when stocks run low.
- Splashes from ancient water can kill a Tarr in one hit, regardless of the time of day.
- Before Ponds were changed to provide unlimited water like other water nodes, Ancient Water could not be used to fill them, though the regular water left over from the effect could.