6th week bloom, purple slh, blue hawaiian, pre 98 bubba kush HOW SHOULD I FLUSH?

First grow, Fox farm soil, Advanced Nutrients, 400w hps, will upgrade to 1000w air cooled on next grow. 38 days in Any tips on flushing methods would be appreciated, as would any other feed back.

http://www.youtube.com/watch?v=N1rQlq3ikQ8

Thanks