Beginner question

[tjshea]

I am about to change my reservoir for the first time. I am running a dutch bucket system that I have made out of 2 gallon buckets that a restaurant supply company was going to through away. I am using a mixture of perlite and Coconut fiber as my growing medium.

Should I flush the growing medium with warm water every time I change out the reservoir?

I apologize for my spelling.