The cube is only filled 2/3 total so the other 1/3 will be filled with some more of the same rain water later. In the shop they adviced me to ad only a 1/4 of the total volume with normal tap water els some of my values would crash. The next 1/3 of rainwater will be heated and is going through a coffee filter with crushed/shredded to get a the PH more down, something similar like running it through a coffe machine.
The
PAROSPHROMENUS PROJECT
