that s not normal look..
def of P, K, Mg
ph problem or parasites on the leaves or both
check this chart too
View Image
250 hps ? is far away if it is 400 than ok, but rule of thumb with hps, if you don t have cooltube around it, put your hand under the bulb, where the plant is, as long you feel comfortable, it is ok to the plant, as it getting hotter to you to keep your hand there due to the heat, the plant will burned there, easy to check.