Not Sure...1st time grow

So i am about 6weeks in from seed, currently using 8 23watt(100equivelant) cfl on a 18 hour on and 6 off. I started out using Mg potting soil with a mix of sand,perlite and organic mix and ive been giving nutes(Mg tomato) for nitrogen every other feeding mixing .5tsp/1gal of water. Just recently started to notice few lower leafs turning yellow, not my main concern bc i feel they just dont get all the light they use to! My concern is one plants leaves were stating to look alil dry and brown speckles, these speckles are starting to cover the plant and i dont know why or what is the cause ive enclosed a few pics any advice or understanding would be great...Please and Thank You in advance!!!!

Stop feeding them so much. Feed once a week

Is that the problem, I've been watering every 5-6days?

way over-fed............stop. just water for now.

Most MG ferts do not contain any calcium or magnesium. Being its the lower leaves and looking at the pics I would say its a deficiency of both. Give us some pics of the entire plant because nute burn usually shows up in newer, upper growth rather than the lower, older growth.

So i wanted to wait a week b4 reposting just to keep an eye on them an see if conditions worsen, spread or stay the same! So far doesnt seem to be getting much worse the yellow leafs have become more yellow and brown,really dry but i am noticing its starting to happean on another plant too... Heres updated pics of whole plant hoping you can tell a little better what the symptoms are or whats the problem so i can work on fixing this!!! Plz help..