Problems 1st week of flowering

I am a first time grower and am having some problems growing. I have 6 plants and using a 430W HPS. For the last couple month I have been having a problem with the tips of the leaves turning yellow, then brown, then curling and dieing. About a week I transplanted them into 1.5 gallon pots and changed the lights to 12/12. Since then they have grown like crazy and the new growth does not show signs of the curling. Should I be worried about the older leaves? I attached a few pictures but they are not the greatest. Sorry. Any help would be appreciated.
Thanks alot

looks like you might have some hot spots that are creating leaf margin burn then eventually kills off the rest of said leaf, most of the time its a very slow process. Just make sure that if you put up a material for reflection purposes, you make sure that there are no wrinkles in it. None at all. Also, with that many plants under that one light, I would reccomend very little vegging, because the taller ones are going to fight for the good light(majority of useable lumens). Plus the shorter ones will never grow as fast and vigirous as the genetic winners! Let me know! You could also have a nutrient defiency, or be overwatering them. Flush them with high quality H2o, and make sure you dont water again for atleaast 5-7 days. Then dewrinkle your Mylar, or whatever it is that you are using. Just buy a cheap white poly, and cover all walls! Works just as good.

Dewrinkle your reflective material, it is creating hot spots! Also, get a fan in there too cool those ladies off. Watch over watering them! You could also use a higher humidity. And if U are going to roll that many plants under one light, I would get atleast a 1000 or a 600 watts HPS. You will see an incredible difference. Uniform Canopys all around, Thats the Key. Let the plants race for what they want naturally. Just start them at equal sizes, even if u have to LST. THey are so more durable than people think. Remember this; it wants to grow, don't force anything! Be patient, stick to the basics, and don't handle them much. You do this and I guarantee some great Success. Flush those ladies if it gets worse, hell you might want to anyways if you think U might haver overdone it on the plant vitamins! Good luck!