HELP! Yellowing of leefs on new seedlings

[Milldog]

Hi. I've just started my first auto grow and there on day 5 above the serface and on 2 of them have just started to go yellow any ideas I've got a 1.2x1.2meter tent a 600w hps dimnerble and have only had it running at 250w I've got a 4inch out take a 12inch osculster on now I'm just wundering if I should turn the light up to 400w and have it about 12inch away can anyone help please

[Eliot Pryor]

The light is not why the leaves are yellow but going to 400 and 12 in. above sounds alright. Have a great grow !!

[Milldog]

Thanks guys I think I know what it is now I started to add half the amount of rizotonic it says for week 1 thinking that would be OK but I will go to just pH water till the next set comes through thanks again