Been using Grodan for years. I was just curious as to what others were doing. I'm basically doing the same sort of times/durations as you are with the 6's. I check the run off and adjust accordingly. I first started in soil, literally dirt from the garden and some Durban poison seeds that I got out of a bag of compressed crap, it was mostly sticks, if you saw it today you would laugh them down the road for selling it.6x6x6 blocks with four 2gph emitters per block.
pump runs once a day up to 3x a day, feed to run off each time. I go 10% plus.
time can be from 4 to 7 minutes each depending on growth stage and number of feeds per day.
what made you choose the slab form of rockwool?