Help, young leaves are curling, drying and breaking!!

Hi, can anyone help me with some advice? I have some leaf problems with my plants and Im hoping someone already seen the same problem and knows what it is and how to fix it.

I have two white widow and one durban poison, this is my first grow, we're at the beginning of 3rd week in flowering. During the veg period (4 weeks) i used a fertilizer with NPK 6:4:5. They were doing ok. Last week (second week of flowering) used another nute, after trying to find something good for flowering and not being able, this one had NPK 3.5, 7.5, 7.5, it was something cheap and made for cacti (that what it said on the bottle). Added to the water following the instructions and watered the plants that night but by the morning some of the top leaves and few from the middle were not looking good (i will upload some pictures), still dont know if that was a coincidence or not. Of course I never used it since, i only watered with H2O2 added, i watered everytime until the plates underneath the pots were filled with water, threw away that water and watered a little more so that it reaches the plate again, thinking that this way I will get ridd of the bad nute. The leaves are still far from ok, its been a week and a half so im wondering if its not something else... The pots were becoming too small for the plants so I moved them into a bigger pot, this one has 90 litres. I dont know if it was because the roots didnt have enough space, i doubt it, the plants gained in height a lot during this past week. I looked for insects, stuff like that, someone told me it could be from bugs but I found nothing, the leaves are clean. Could be lack of nutrients (since i switched to flowering the only time I added nutes was last week - that bad episode). I ordered some BioBizz, i should be receving it next week but until then? Should I add some nutes from the one I used in Veg period? Or leave it alone until biobizz arrives? Or maybe they have another problem im not aware of? Could be heat? I have one 250 hps and 2 cfl, the plants are a bit close to the lights but it doesnt seem too be so hot. What do you think I should do, any advice?
Thanks

how is your ph..? do you check it..??

your nutes should have #s like 12 6 6 for grow and 5 10 5 for flower make sure your ph is 6.5 or you will lock out nutes causing probs

No, I dont. Never did (i didnt find anything on the market that I could use). The plants were fine. I only water with bottled water, Ph 6.5 and the soil has a ph between 5-6.5. As I said, everything was fine so never thought that Ph could be a problem, I was happy that, since I have nothing to test it with, the plants are doing ok.
Since I still have nothing to test the PH, what should I do? I transplant the plants last night, they now have space for the root and new soil, also with ph between 5-6.5.

I must say overall they look good for 3 weeks flowering-they do look a bit hungry though-overall light greenish. first three weeks of flowering most critical point where alot fail. plants entire biochemistry changes and this period is the time it happens. so nice job so far. I would def. add some Fine Dolomite Lime from your local garden center to help with buffering the ph and provide the most essential magnesium and calcium. 1/2 inch layer or so mixed in with first top inch of soil. you can give them a half dose or 3/4 dose of the veg nutes for the next week and a half. Because your girls are borderline deficient, if you cut out their N now your fan leaves will yellow rapidly which you dont want. you can also add some black strap molasses which contain high levels of P and K.
those leaf issues- I would check again and than one more time for thrips. More likely there are hot spots in your reflection causing the leaf tissue to heat up to an unsustainable level and literally burn right off. raise the lights a hair as the bud sites are formed and her height should stop increasing.
some girls stretch like crazy in the switch from veg to flower and some do not.
u can pick yourself up a cheap aquarium ph test kit from walmart for like 8.00us.
the spotting looks like ph issue-remember the lime will buffer the soil, but you want to adjust your plain water ph to 6.8-7.2 and your feeding water-after nutes added-to the same thing. than test your runoff and make adjustments to the water ph accordingly.
what are the NPK for the Biobuzz?

Thank you for the help. Lets see, I've read your post two times to get a better understanding of what you said. English is not my first language and im not in the us, im in eastern europe and some of the things you said I should buy I dont remember seeing in the shops, for example Dolomite Lime. I will go today and ask around, see where I can find it. I will water today with 1/2 dose of the nutrient I used in veg and see how they react, I was a little afraid to do that but now that you mentioned it, why not?
There are no thrips but will check again, and again. Something weird is going on because all 3 of them have been staying in the same place but only two are having problems with the leaves, one white widow is fine, this one was also the biggest and strongest one in veg, after flowering they all kinda grew the same. Now, those other two are higher than this one but even tho she's smaller in height, she's a lot more bushy and with no leaf problems. I imagine that if there were thrips, they must've been all over her too by now. So it must be something else.
Didnt know what molasses mean so I looked it up on wiki and saw that is a syrup. Hopefully I will find it here, will go looking for it today but if not I have no idea what to use instead.
I will raise the lights a bit even tho its quite hard, i've modified the grow closet lots of times and right now I have to come up with something else in order to raise the lights a little more, we'll see.
I have a method for checking the water PH, I thought jats was asking about soil PH. That I cant measure but I have some strips for water Ph and have been using those to find a good water to feed them, the only problem is that the strips show a color and I have to look it up and see where is located (I have a diagram with colors and ph level for each color.) ITs not that accurate so I will look for something that shows some numbers
Will check again the water, the water with the nute and the runoff (never checked that before) and see what it says.
I ordered biobizz because i couldnt find something else that could be delivered to my country. NPK for topmax biobizz is 0.1, 0.01 and 0.1 and biobloom has 2, 6, 3.5. I cant really say that this is what I wanted, had no other options but searched for some reviews and saw that other people use it, the plants are looking ok so how bad can it be?
Thanks again.

What are the white dots on that lower leaf in the picture.

I was just watering them and found some things on the leaves, some particles I cant identify, here and there, my grow area has the upper side uncovered, a lot of small things can reach the plants. Now im a little paranoid and wondering if they are not thrips. If there were thrips here should I be able to see them? Do they move?

the white dots are trichs i think and they sparkle from the flash. Took some more pictures, a lot more, I will upload, do you see anything??

These are taken from the one that's intact, I havent found one damaged leaf on her... I see no difference, the small particles appear everywhere, a lot of dust also, trichs and pet hair (I have pets and cant keep the hair out of there).

Have you tested what is the EC of the run-off from your pots.

No, i didnt have enough water, forgot (pft, I smoke too much) they now have a 90 l big pot so there was no runoff and plus the pot is huge and I have a hard time lifting it up. I will get some more water and some help Will get back with the results later.

Oh wait, by EC you mean water PH? If not, I dont know what EC means and how to test it.

EC means electrical conductivity. But Im thinking in your case it wont be the EC since you have not used very much nutrient.

One other question. What is the soil you are using.

If you need help in how to properly test the run off from your pot using thoase pH strips then check out the video on this page:
http://www.ganjaguerrilla.net/calendar.html
Called PH and Flushing Streaming Video

On the video they dont use the strips but that is how you test the pH of soil, and instead of doing what they do by using the pH wand, just dip your strips into the runoff and test the pH.

Also do not use any more vegging fertilizer. If you are in Europe and are unsure which bloom fertilizer to use, may I suggest that you go to a hydroponic store and purchase Tera Fores by a company called Canna. This product is made in Holland and is common all over Europe.

Also I suggest you purchase both Cannazym and Rhizotonic as additives to be used along with Tera Flores. This will help with any damaged and rotting roots, and also help your plant quickly fill up that 90 litre pot with nice fluffy white roots.

Your plants look to me like they are at a critical stage where they need the correct soil pH and the right fertilizer - acting quickly and acting correctly will save them.