system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: if Borax increases the effectiveness of laundry detergent why is it not a default ingredient in laundry detergent?
gpt
It is a common ingredient, but it's very alkaline.  That gives it water softening properties, but also side effects.  It also doesn't dissolve well on cold water, and hot water can have other side effects on clothes.