8 day old plants with yellow tips

Ill ty to give you as much info as i can don't have any pics plants are about 8 days old under a 250w hps metal halide conversoin bulb temps runing about 80-85 in grow room i think it might be a problem with the soil on the bag it says Total Nitrogen .009%
0 0.5 Ammoniacal Nitrogen
0 0.4 Nitrate Nitrogen
Available Phosphate 0.06
Soluble Potash 0.05
Its GardenScape pro mix Says it has Sphagnum Peat moss Organic Compost
Composted and aged softwood Bark fines
Perlite
vermiclite
Dolomitic lime stone

I have not gave them any plant food since there so young they seem to be doing great just a day ago the the looks like the tips of the plant are burnt or drying just the tips so far some on both sets of leaves others just one 4 plants in all
thought it could be Nutrient burn so i flushed the plants with rain water ph of about 6.8-7 and then tested the water that came out of the pots was at a ph of 8

Only thing i can think of is Nutrient burn or maybe the light was to close i rasied the light and flushed the plants

Ok any advice you guys can give me the i know i need to get the ph down for one thing not sure waht to use for that and should i be looking for new soil for the plants

looks like it turned out to be a heat issue the plants seem to be doing ok not geting any worse still need to get the ph where it should maybe flush them again in a few days with ph ajusted water