White spots on top of leaves

[wildman21]

Hello,
Today I discovered a few white spots on my leaves. Can you tell me what these are?
1st off, I did have knats and added beneficial nematodes and sticky strips. Knats are gone.
2nd, I installed a new LED light earlier in the week and determined the light was too close to the plants, because plants became very droopy, so I moved it higher higher and plants are not droopy now.
3rd, I looked closely and do not see any evidence of spider mites unless these spots are caused from them and I'm either not seeing with microscope or they are gone.
This is an indoor grow in grow tent, Mars Hydro LED light and Fox Farms Ocean Forest soil in fabric pot's. Veg state. Thanks

 

[GNick55]

either dust from perlite,
bugs pests,
a form of leaf septoria?

 

[Aqua Man]

Yeah think its just dust or something that fell when changing the light.

 

[wildman21]

I should have said, in regards to something falling when I installed the light. This is a new tent and the plants were not in it when I installed the light. They were in it when I raised the light. Also, I have 1 white widow and 1 northern lights and this is on each plant. heres's another pic i took through jewelers loop using my phone. It does not wipe off as if it was a particle that fell on the plant. Other pics do not show as ring, but as solid spot.

 

[Aqua Man]

I should have said, in regards to something falling when I installed the light. This is a new tent and the plants were not in it when I installed the light. They were in it when I raised the light. Also, I have 1 white widow and 1 northern lights and this is on each plant. heres's another pic i took through jewelers loop using my phone. It does not wipe off as if it was a particle that fell on the plant. Other pics do not show as ring, but as solid spot.

Looks like some trich formation.

 

[GNick55]

probably leaf septoria

 

[wildman21]

I do not see this on lower leaves, but you may be right. This is my 1st grow.
Someone said Trich formation? I hope thats it. Plants been in veg 2 10 weeks.
I will monitor one leaf to see if spots enlarge.

 

[wildman21]

FYI, this was caused by hard water in ultrasonic humidifier causing mineral dust.