I assume that you are using hempy buckets. Why don't you change your medium to hydroton instead of perlite - has a lot of advantages - the main thing is the rinsing problem.
This is what I do and it seems to work. I take the 20 pound bag and cut several holes in the bottom of the bag. Then I take the hose and just run water thru the bag from the top until the water comes out clea from the bottom.