I have 5 power skunk auto plants on the go they are about 8 weeks old with no buds they started showing pistols about 20 days ago and haven't changed and need help asap. They are in 10ltr pots using soil, I have been feeding them bio-bizz nutes, they were under 20/4 changed that to 18/6 last night, using a 600whatt hps bulb they are 27inches tall and just seem to keep growing taller my light is atleast 50cm from the plants tip