Mari+Mo

yes, carbonated water burns marimos because it's literally acid. do NOT put marimos into carbonated drinks, it will kill them from the inside out - it's worse than leaving them in direct sunlight for hours. do not even put them into carbonated drinks as a "treat"/once in a while. a better "treat" is sticking them in the fridge for the night, if they like that. alternatively, ice cubes are also a good "treat."

rainwater and distilled water are ideal for them, but rainwater carries the risk of parasites and unwanted algae. tap water and bottled water isnt ideal, but will work fine if your marimo isn't picky.

you cannot help a marimo grow faster - they're inherently slow-growing plants, growing at about 5mm per year. the best you can do is keep them alive by giving them daily cold water changes, and keep them out of direct light