The flushing problems I had came from trying to flush the medium during the grow, because of the way the pots work, excess salts are pushed to the top where they can't do any harm, so now I'm just leaving them. They are gravity fed from the rest, I'll normally turn the valve off for two days, then on again for a day, it's worked pretty well.
I've never used organics, but it's been on my to do list for awhile.
They were flowering for 66 days, I left them for about a week too long cause I'm lazy, I really need to buy a trimmer, haha.