Usolved Mysteries, Can you solve this problem? ps First ever post please help me!!!

OK so Ive been down this road before and here it is again,, But I cannot figure out this time exactly what is going on here. my PH is a lil high so next watering im going to bring it down with some "down" (im not far off just around 7.2) so im going to water with 6.3.... I know it seems like a cal/mag def, but ive been giving a light supplement of cal/mag every watering... which is where I think might be the problem??? since I am using tap water there really isnt need to supplemental cal/mag ive learned so i think i may have over done it causing a lock out???
so my questions are.....
what are your inputs????
If i water 6.3 and stop with the cal/mag should this correct my problem????

P.s. i have a light infestation of spider mites and that is going to be cleared up quick cuz I brought hell upon them this morning and will continue to bring hate and discontent to them until they are gone...
I have attached pictures as well as a cool macro shot of my Icy ladies (new phone has macro feature!!)
Strains are White Widow (whos showing the worst signs), and ice & chrystal

Spider Mites are the problem

tomorrow is water day so im going to use 6.3 of plain water then the next watering 6.5. then feed on the third and get them back on schedule

Those big holes are not spider mites. they may have helped.
When you say tap water what do you mean ? well ? city,county ?
I ask because how much poisin is too much. I know soil is much more forgiving than hydro but in a container is similar.
Save your self some problems and get distilled or R/O water and add only what you want to it.
no guessing, you know.

by the way it looks like some kind of chlorine or iron problem. mighty wash is the stuff for mites and if you spray it in your face you want even get sick like azamax poisined me.