But that’s not likely due to co2 concentrations but perhaps other toxins
Why do you consider it more complex? Capture rain water. Run it through RODI. For some might be the only option
I have no idea what’s in local rainfalls so I can’t tell if the RO process or the DI process is effective.
To me, it’s easier and safer to start with tap water in most cases, especially if it’s a good large city system.
With factories emitting all sorts of chemicals into the air, this soup is going to make it into the rainwater, and then, into your reef system.
Is that an issue? Maybe or not, it depends a lot on your local rainfall.
If I had no choice, sure, I’d use it. But then I got to collect it, maybe move it, then pressurize it.
My tap does all of that, but of course, for a price.
We are lucky to have great clean delivered water in our city at a very reasonable price, so for me, big city dweller, tap is so much easier.
But I completely respect other sources as well, each comes with there own unique challenges.