Rust-ish spots on some of the new growth (pest problem???)

Indoors, in a 3'x3' closet, 400W MH w/ 265 CFM air-cooled hood, being fed with RO Water, Lucas formula and CalMag+ at 1.25 EC (875 PPM on .7 scale), res was changed on Wednesday before problem started appearing and exact dosage was:
2gal RO water (000 PPM)
10ml CalMag+ (brought solution up to 210 PPM)
10ml FloraMicro
20ml FloraBloom (brought solution to 875 PPM)

When I mix my nutes the PH mixes out to 5.5. It has risen to 5.8 by today. For the previous res change it went 5.5-6.3 in 12 days then I changed it. The res has had no PH UP/Down in 2 weeks. It hasn't needed it.

Prior to the res change I was running in the same ratios but the EC was 1.35 (950 PPM) was noticing slight nute burn on the tips so I dropped it slightly.

It's growing in a DWC and is currently on day 22 of veg from clone. Not sure how old the clone was when I got it. It's in a 1.5" rockwool cube planted in the hydroton in the netpot.

I'm noticing these spots on some of the new growth, probably 4-5 leaves are affected.

Picture 1 is from yesterday when I first noticed the issue. In person you could see "shiny" spots on the leaf where the rest of the spots you can see on Picture 2, 3, and 4 (today) formed.

One of my buddies said spider mites, is this what this is? I've been looking at pictures but they don't seem to leave rust spots like this

Radiant heat perhaps? what are your temps?

New growth and rust spots=calcium deficiency......and thats what it looks like too me......

dimajna said:

Radiant heat perhaps? what are your temps?

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Room temp 75F, Res temp 65F, colder for the 6 night hours

watchhowIdoit said:

New growth and rust spots=calcium deficiency......and thats what it looks like too me......

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Looks like that to me too, but I'm already using CalMag+...

From some reading, it might be that too much P and K in the Lucas formula locked out Ca?

So I'm thinking of switching from the Lucas formula to another line of nutrients. Going to go to the hydro store tonight or tomorrow and pick that up.

I've had a few problems with this (my first grow), both nutrient deficiencies and multiple people (both online and in person) have been blaming the lucas formula, saying I need to use a real grow nute during veg.

I'm not sure what nutes I want to switch to, thinking of AN Sensi A+B, Dutchmaster Gold, or Dynagrow..

any opinions on this are gladly welcomed, don't want to spend more money than I have to but if the lucas formula is what is causing my issues I will try different nutes.

Dyna Grow is your best bet...