I’ve tried it a couple times and I’d suggest using a genetic that you’re familiar with and know the exact finishing time then count back for your start time

40 L is about 10.5 gallons.

Recharge has all the correct endo-mycos. Hard water high in calcium will be alkaline. If it’s too alkaline (above 8), you’ll want to lower it to around 6.

Minerals like calcium make water hard. Not chlorine or chloramine. You can’t evaporate calcium.