Can't identify my problem to save my girl. Help please!

I picked up a white rhino clone about 3 weeks ago, and it had what appeared to be some minor ph burning on some of the leaves. I started trying to treat the plant for this and saw no improvement. I then looked through the forums and came to the conclusion it must be a calcium deficiency. I have never had a calcium issue before so this is a new experience. I had been using 5ml cal mag plus per gallon for about a week and things were looking great with just a little tip burn on new growth. Then I left for three days and when I came back I found my older large fan leaves looking splotchy with black dots across them. There are no insects I can find and the bottom of my leaves look healthy. I just didn't know if this was to be expected since the old leaves had a calcium issue or if I have a bigger issue that I haven't identified. I appreciate any help I can get. I plan to change water tonight.
Hydro
Fox farm nutes approx. 3/4 of their suggested levels
5ml/gal calmag plus
12/12 for 1 week
Using spring water
pH 5.5-6
Lights on temp approx. 83 lights off approx. 75

My plant with some of the splotching visible

One leaf in normal light

The spots...

It does have a pH/lockout look. And yet you seem to have the pH issue in hand. What are the ppm of your water and your nute solution? When you say spring water, do you mean bottled? Your own RO filter may be a good investment.

The other possibility is a bad pH meter. I'm sort of guessing, obviously. cn

? wtf. looks like some disease

Can't do ppm right now. I'm going to buy a new meter for both this week. It is just hard to get out with work right now. I use water from one of the machine for filling 5gallon jugs. It may not be ideal, but the use RO and other filtering processes. Plus prior to this plant I have never had a problem. I removed my nutrients from my reservoir in case they were possibly tainted or the cause. The cal mag was brand new so I put 7.5ml/gallon in. If I see an improvement I'm guess it is my nutes if it gets worse it is my calmag and if nothing changes I'm right where I started out.
I took a few more pictures with the plant under normal light. I have tried looking for the symptoms I'm seeing, but all I find are people with thrips or something they believe is mold/fungus. I have looked everywhere for insects because I can deal with that, but there is not a single bug anywhere. I'm also 99% sure there is no mold present on the plant or the roots.



This still looks like a calcium issue to me, but at this pH and with the calmag I don't know how it could still be progressing. Also in all the photos I find of it i see no black dots like my plant shows.

The leaves look dirty, but they aren't. They're just fucked!

Looks like I had some heat issues with the plant getting near the lamp while I was gone, but I don't see how that could cause this.

This leave looks healthy, but also extremely dark green. It is part of the reason why I pulled out my nutes. In case I was causing an abundance.

Not that it matters I am using a 250watt hps and have the plant in a gl60 tent. My exhaust fan bearing burned out so I am keeping the tent open during light on hours.
This plant has gotten larger than I intended, but I don't want to see it go. Any help or calming words would be appreciated.

My plant started doing what looks like the same thing minus the black. Mine just has the little brown circles. But I also thought calcium was the issue. So I went and got some dolomitic lime and just fed it. I will let you know how it turns out