Leaves spots! Help to identify this problem / s ?

Hello, can someone help me identify this problem?
Plant are auto grapefruit from FastBuds on day 40, in 11L soil (canna professional with extra perlite) pots, under hps (400w in cooltube)till 2 days ago , switch to LED (mars hydro ts 3000) due to external hot temperature.
Nutes schedule A+B (bloom) and explode , both from Dutch Pro, followed producers chart, ph in range on 6.3 , ppm (last) 712 .

Probably I had thrips, used a bug repellent spray and add a layer of diatomaceous earth to the soil aprox 10 days ago (I understand that it blocks their life cycle) .

Here some pics of leaves , what do you think ?
Thanks in advance.

Shall I post it on a different section? "Autoflower" or "plant problems" ?

THRIP damage,a little heat stress.WHAT is your question ?

Hi Myke,

Thanks for reply, question is what can cause those spots ? You think is thrips still doing their thing plus some heat stress ? Not nutes burn or calmag deficiency ?

Matfkn said:

Hi Myke,

Thanks for reply, question is what can cause those spots ? You think is thrips still doing their thing plus some heat stress ? Not nutes burn or calmag deficiency ?

Click to expand...

Hard to see,but thrips will leave those spots

Can you post pictures of the whole plant? Do you see any bugs under the leaves?

Hi, that’s the point, I was unable to see any bugs/larvae or black spot (poopoo) under leaves, in my opinion plants look healthy, pics are from 5 days ago, while those are from today , but I’d like to different opinions from someone more experienced than me. Thanks