Yes, the Water Generator, the Green Acid Generator and the Sewer System are not available anymore by the way of cheat keys. What was said in the manual was wrong since 1.21, so we corrected it.
The cheat keys were removed in the 1.21 because in this version, most Items gets an official way to be obtained with game mechanics. Some get a mean to be made, others were placed in the world. The Water Generator and the Sewer System are now used in the world for the waterfalls in the Big Canyons zones that where added in this version. At the time, these can be collected with any tool. In the future, we may made these blocks only collectable by robots or special tools.
So, we can confirm that the water is an infinite and renewable resource in Blackvoxel.
We said that most items was used in the world or get a way to make them, but there are exceptions like the green acid generator that can't be get at that time. An official way to get it will be re-introduced in the future.
[spoiler]
At the time, yes, hacking the inventory file can be done to get it. That's in the PlayerInfo.dat file in the universe save directory. The Green Acid Generator is VoxelType 92. The inventory is at offset 164. There is 40 main entries. Each entry is made of 2 bytes for the VoxelType (Indicated in the manual) followed by two reserved bytes, followed by 4 bytes for the quantity.
If you want to try a (very) cheated and (very) overclocked robot, try the VoxelType 158.
[/spoiler]
The Blackvoxel Team