Our betta was not doing well today and I got some GREAT advice here (thank you again, LittleBlueFishlets!

), a part of that was to put our little guy in some water with epsom salt which appears to be helping...
Anyhow, I did 1tsp epsom per gallon in the WHOLE TANK and then slowly acclimated him to it. Now someone has told me that epsom is supposed to only be used for like a 15-20min bath.
Is it ok for me to leave him in a tank that has epsom in it over night, or even the next few days? or did I misunderstand and I was only supposed to be putting him in the epsom water for a short period? Thanks in advance for your advice, I am super panicked now!