help! young autoflowers in danger...

I have 3 fast bud fem. seeds that just sprouted and the first set of leaves are already turning yellow, i was thinking it might have been because my 400w hps may have been to close or it may be the city water im using..ill attach some pictures and if someone could please help me ASAP that would be excellent!

Thank you

looks liek theri burning. are you giving them nutes or does the soil have nutes in it

i havent used any nutes im just using normal fox farm oceans forest

i have heard ffof of burning plant that small. so my bets are on nute burn. are you temps ok and are you checking you ph

damn no i have not yet i will need to go purchase a ph reader tomorrow. my temperature is a little warm since i got the 400w in a small closet with mylar and a small fan.the light is about 2 1/2 feet above the plants and has about 3 more feet to move up.

my bets are still onburn but it is always good to know the ph of what is going in and the room temp. and it should be high enough from the plants to not be burning them