If stirring kalkwasser has negative effects, why do kalk stirrers exist?

[RT_BRS]

FAQ #31: If stirring kalkwasser has negative effects, why are reactors available that do just that?

When running kalkwasser in an automatic topoff, or DIY dripper system, mixing the kalk after the first initial mix has the negative effect of introducing atmospheric CO2 into the mix essentially reducing the effectiveness of the solution. So why are there kalk reactors designed to stir the media? How have you guys implemented kalkwasser in your systems?