my babies are looking very sick.

so, i have a small closet i am using for a mothering/clone chamber and up until recently i was doing just fine. i have a decent amount of clones that have been growing in the closet for about 3 weeks since rooting, they are in 1 gallon grow bags (plastic), pro mix, 400w mh, 4 inch inline fan for vent, watering about every three days or when top inch or two of soil is dry, 18 hour cycle, during the day from about 10am-6pm i open the panda film door to allow the air conditioning and fans to access the closet as well. i have only given them nutes once at regular dosage (humboldt nutes) and i thought i had spider mites a week or so ago so i gave them a very diluted dosage of azamax (about 3ml per gallon). im just not sure what this is, nothing ive seen before. any help is much appreciated. i like tomato

Picture 1 is magnessium def.,
Picture 2 looks like salt lock up,
Picture 3 means the pH is off the correct level,
& Picture 4 appears to be spider mites.
Look under the leaves for those!

ok, i had a feeling about the magnesium. as far as 2 and 3 goes, could these both be corrected by flushing with ph'd water and possibly epsom salt. and is it ok to give baby clones that have barely just rooted azamax? also what is the best ph for promix? thank you again.