Irish Smoker, first crop, little (I hope) problem......

Hi,

I am roughly 10 weeks in (yes, I should have kept a journal) and my 3 plants are coming on pretty well. Flowers are getting bigger daily, trics appearing all over the place and starting to smell sweet too. I am having a problem and need some advice. I was given the seeds and it turns out they are 3 different strains!! Hairs are starting to turn brown on one plant but hardly any on other 2. I noticed the leaves turning yellow and curling a few days ago and it looked like magesium lockout. I tried Espom salts for a few days (mixed with usual water & fert mix) but the problem seemed to get worse. I flushed all 3 last night and removed dead fan leaves. They look much better today but I have no idea when to harvest them. One plant has about 10% brown hairs, one has about 2% and the other has none. Im not sure what to do now as I dont want to over feed or underfeed my babies as they are real close to harvest and its my first go!! Please help.........

the yellow leaves where from nute burn so its a good thing you flushed it dont be concerned with the hairs but be aware of the tricromes when 50% are milky color or cloudy then you harvest feed every other watering and stop watering when you have 2 weeks left

thanks for your response ts. I am having terrible trouble getting a 30X magnifier in this country (ireland) so thats why i was looking at hairs. is it possible to judge by looking at hairs alone?? my flowers are pretty decetn looking but i have no idea how long they have left... the plants are at different stages, would I do more damage overfeeding then underfeeing?