my ak48 needs help guys :-(

hey guys can anyone tell me wht is wrong with my ak48 ? leaf tips turning yellow and crispy to the touch, 4weeks old, 7inches high, under 400mh lighting,hav'nt started using nutes yet. Please help me guys

2 letterrs, PH-CHECK WHAT YOU PUT IN AND CHECK WHAT COMES OUT THE BOTTOM. WHAT COMES OUT OF THE BOTTOM IS IMPORTANT.

Mine have been doing the same thing lately and Im about a month in as well and they are about the same height. I recently I added dolomite lime cause I thought my pH might have been off and so far it seems to have stopped or slowed the problem. The second picture is probably pretty similar to what your seeing, the first picture is another thing that started happening as well and if were having the same problem it might happen to yours too (light green bands)

thnks for replying,how did you apply the dolomite lime ? and did your plant return to normal ?