15 mls per 3 gallon pail right? So 5 ml/gal? That's a good but low rate.
Under open hood, 1000 watt bulbs, and co2 addition, I'm pushing up to 2.0 ec now.
I'm following a guy doing 4.0 ec on Rockwood and his buds are rock hard. That's 2000 ppm. Very high, only a pro should do that that knows how to cut off feed a few weeks before and let the plants eat themselves. I don't like going much above 1000 ppm in my setup. You are likely only at 500 ppm which is too low. It's counterintuitive, but feed more. The plants wanna eat.
I'll add this: yes I have noticed varying ripeness. Again this is the plants being allowed to fully express their genetic.
In the above photo, I have found the white OG to be done, fully cooked, at 8 weeks. The strain next to it will go 10 weeks easily. I grow them together. Might leach down on the last feed at 8 weeks for the White OG,and then continue to drop for the last 2 weeks until chop on the dosi. Both smoke great, as long as I don't overflush them. That causes lockouts and terrible burn. Right at the finish line.
I do use the white OG for hash, so flush matters less. For bud, a nice white ash and even burn are enhanced by letting g the plant start to eat itself around week 6. By week 6, you should be at peak flower feed for most strains. And wind down from there. I used to feed too heavy in weeks 7 and 8, and no amount of flushing or leaching until 10 weeks will eat it all if you do that. Peak at 6, wind down to 9. Chop at 9 or 10 weeks unless you got a real early strain at 8. (Make hash out of the 8 weekers, thank me later ;) Happy smokes