What does RO water for the aquarium mean in practice?
Low GH and KH levels allow you to build your composition from scratch using salts intended for a specific cast.
When does it matter?
Pure permeate should not be automatically fed to all organisms as it may not provide the required osmotic balance.
Which solutions are related to it?
It is mixed with source water or remineralized, controlling conductivity, GH, KH, temperature and stability before replacement.