A small amount of glucose helps with fluid absorption. There are packets and concentrates of oral rehydration solution that would be better and safer than just potassium. Examples include
Jianas Brothers Oral Rehydration Salts
https://www.amazon.com/dp/B00D...cp_tai_5wHmDbR2K4PCB
and with more sugar and probably better taste:
https://dripdrop.com/products/...zEAQYAiABEgL2M_D_BwE