Isn't that what they do? They hook up the GECK to make it work.
No, the GECK does not need hook up to work. The GECK is a self sufficient terraforming device. It doesn't need some computer and a water tank to work.
Which would be awesome were not it is.....river. Which brings new water into a location.
I said water spring. You purify the spring, all the water will be clean. I mean, the river is flowing, it never rains in Fallout 3, so the water has to come from some kind of natural spring, maybe a subterranean water source or something. Purify that source and you get clean water.
If there was no source of water, then the purifier would also not get any water to be purified, the river would be dry.
Yeah, awesome were it a static location like the GECK was meant to be. Mind you, the Fallout Bible explictly says the Tribals of the Chosen Ones were fools who believed the GECK was more powerful than it was.
What does the Bible has to do with Fallout 3 GECK. Fallout and Fallout 2 GECKs were mostly an assortment of survival guides, seeds, some chemicals to remove radiation from soil, a portable reactor and some codes for the vault replicators.
But Fallout 3 specifically changes what a GECK is. As I mentioned above, they changed it into a magic matter disassembler and assembler, that when it assembles the matter, it is radiation free:
Fallout 3 said:
The G.E.C.K. will collapse all matter within its given radius and recombine it to form a living, breathing, fertile virgin landscape and allow life to begin anew
And that is the problem, they changed teh GECK to be so powerful that it can magically fix an entire area making it non-radioactive, "breathing, living, fertile virgin landscape to begin life anew.". If the GECK now does that, what is the point of using it for a water purifier? You can purify soil, plants, water, air, etc just by using the GECK. Do it at the water source and the river will flow without radiation, afetr a while, due to the river flowing, it will take most or all radioactive particles in the rivers path to the sea, purifying the entire extent of the river.
There is no way they could make a purifier in Fallout 3 if they used the GECK as they were in classic Fallout games. So I have no idea why you're pulling classic Fallout GECKs in this argument.