Need help, plant showing signs of both nitrogen toxicity and defficiency

Hi guys, this is my first thread and grow and I need a little help here.
My plant is 35 days into flowering under a 400w hps and until now I could diagnose and treat all of her problems, mostly caused by my noobie mistakes. But recently it's upper leaves began clawing, and by the time I found out it was a sign of nitrogen toxicity I had already fertilized my plant for the first time in flowering. The thing is that at the same time the leaves were clawing, other ones were turning yellow, which I was sure was caused by nitrogen defficiency. The yellowing began in the bottom part but quickly escalated to the whole plant. Nonetheless I flushed it for a week thinking it was better to have little nitrogen instead of too much.
So now I dont know anymore if the plant is healthy for her age and if I should fertilize it again. I am also colourblind so it takes a little more time until I notice the changes in colour. It would be awesome if you guys could help me, thanks.

Are you another defoliator?

I defoliated it one time in veg

Cpappa27 said:

Are you another defoliator?

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i don't think so. just minor bottom removal, the rest looks natural. some yellowing is natural when the plant starts to hit late flower. your a little past the normal yellowing though. some plants are also natural curlers. some of the northern lights strains I've ran like to curl on me no matter how little i feed them. it looks to me like under feeding or a calmag issue. i can't be sure because you didn't offer the type of soil and the amounts of what you've used as fertilizer and the other good important details but id say that the plant will be fine. if your not using calmag then get on that and its in a really heavy stage of feeding right now so try to give it enough food. a cheapo ppm meter would really help you to know what your really putting in there.

Cpappa27 said:

Are you another defoliator?

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little cranky today are we

oh and that defoliation isn't really productive, good call cappa.

Terry385 said:

little cranky today are we

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It's my time of the month lol

have you tried to amend some humic into the soil?

How much and how often do you water?

Do brown necrotic spots show up on the yellow leaves?

Constant under watering will lead to symptoms like that. It will start to yellow at the bottom and then spread fast. Then brown spots show up then the leaves die.
I know some say to cut back on water during flower. Don't cut to hard.
A proper flush may be in order

OK you did flush. I agree with the concesus that some yellow is normal. Just keep an eye on it what ever caused the yellow may cause more before it levels out.
Don't panic And keep an eye on new growth.

I water when the soil gets dry, like once every two days. I had problems with overwatering in the beggining but I'm sure I'm doing it right now. The plant is in a 15l pot, with a soil mixture that now I know its too hot, I'll get the details later after I check the products.
I bought some Peters flowering fertilizer thats 9-45-15, not sure if its got enough calmag but im gonna give it a try. The product says to use a teaspoon for every liter of water, should I use a little bit less?