Thought its Auto but i was wrong - What do you think?

Hi all,

Long story short...i got 4 seeds from my friend, he told me its Royal Dwarf Auto but
after i gave it all the Auto needs (lights..) i noticed that its not going into flowering period so
i asked here what to do and finally just changed the light schedule to 12/12, I hoped to
see some flowers and I did! seems like its not Auto after all (its small and fast like auto).
So...its my second grow, and here is my setup :

250w Dual spectrum HPS - using for veg&flower
Soil : Coco+perelite
Nuts : Sensi Grow/Bloom
Temp`s : 77-80f lights on/ 66-73f light off
Lights schedule : 12/12 (for 6 weeks)
Seed : Unknow
Ppm : 1800-2000
I flushed her twice till now with Ph`d water and a bit of Molasses.

I tried some Scrog and LST on this girl and it seems she liked it =]
its been 6 weeks from switching to 12/12 and i just wanted to know what do you think...
recently i noticed that some of leaves become really yellow and i hope it part of the game
and not a problem that i cause.

Thanks in advance!

More Pics

If yellow from lower leaves then you will want more nitrogen with your next feeding. The plants also like more phosphorus during flowering.. Your plant looks like you gave it too much nutrients because the tips of the top leaves are dead.. I wouldn't give any nutrients for the watering if I were you.

Regarding the 6 weeks.. it typically take 3-6 weeks for any cannabis to mature enough to flower. the finishing time on the autoflowers includes the veg time from my experience... My autoflower went 1 week past the advertised time.. only took 70 days from seed to harvest for Advanced seeds skunk mass and that was outdoors.

plants look real good.

turn off the lights when you take pics

So no nuts at all...only ph`d water? for how long? i don`t think ill see the tips become green again =/
what do you think about harvest time? it seems like i have time till it finish but just want to hear how long
do you think it will take? yesterday i took small piece of flower, looked it in a microscope and it still most clear
trichoms with a bit cloudy...so i got time =] by the way i don`t too much experience but it looks like Sativa
dominant to me, what do you think?

Thanks all for the answers!

any chance to get more comments here?
what do you think i should do..? feeding with around 1800ppm,
just finished 5 liter flush and wait till it dry..only water from now or should
i go back to normal feeding? and how long till harvest do you think she has?

Thanks again