I never heard of cycling a tank in the dark. And you'll get algae anyway. It's curable.
You do honestly need a refractometer. You've had enough salinity adventures. A refractometer is a no-battery, nearly indestructible instrument that will save you its purchase price when you have to deal with fish in quarantine or make saltwater for a working tank.
You do honestly need a refractometer. You've had enough salinity adventures. A refractometer is a no-battery, nearly indestructible instrument that will save you its purchase price when you have to deal with fish in quarantine or make saltwater for a working tank.