Flushing during grow

I am getting ready to start my 5th grow (ebb&flow under 400w HPS.....widow) and I have always in previous grows flushed out my plants every third res change (I change weekly) with clearex to reduce build up of nutrient salts in my rockwool. This grow, however, I will be adding bacteria & fungi to my root zone (I use AN 3 part, and am introducing piranha, tarantula and voodoo juice this go round) and I am curious if the flushing tri-weekly will effect these beneficial microbes, or if they will be alright. Since they colonize the root zone, and continue to live and thrive there even when not present in the res, and I know H2O2 will destroy them, I am worried that Clearex might do the same. If anyone who knows can help, it would sure be a real blessing. So, VicVicious....Earl....any insight.....or of course, anyone else too...LOL
peace
B

OOPS.....MEANT TO POST THIS IN ANOTHER PLACE......SORRY!!! Am reposting it in he correct place (hydroponics/aeroponics)