This is my first EVER grow: From the pictures abov...

Let me be honest with you , with that purple light it is pretty hard to see how the plants really looks like so if you can takes pictures under natural light or at least with the purple light of and a flash. That said concerning the flush it is unnecessary to do it more than a week when using organic nutrients as they are degrading fast by themselves , moreover the flush is more for the heavy feeders who want to wash the medium and the plant from the excess nutrients ( not excess but nutrients that are in the soil or the plant system ). I also remarked that you are talking about brown pistils like if you were waiting on the pistils to harvest ... which is a bad idea as they are not giving you a idea about the trichomes ( trichines are responsible for the effect , when they are clear you have an energetic high , when they are brown you have a stone a d when they are 50/50 it is a mixee effect but I recommend you to make some search about the tooic