Smoething eating my plant or some other kind of problem?

I have two plants and both have same issue.
I don't know if something is eating the plants or this is some kind of nutrient problem.
This is my first grow so I don't have any experience...
Pictures attached show something but I don't know is this dirt and some random particles or what is it.
The particles are so small that is almost impossible to see without magnifying glass. (I took pictures by placing magnifying glass on the cell phone lens and zoomed in on the cell phone)

Please help...

1) Growing indoor (CFL 6-8 inch from the plants)
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2) Watering schedule -
Watering once in 4 days with non ph-ed tap water for the last two watering!!!
No nutrients have ever been given to the plant!!!(except kelp powder once - second to last watering)
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3) Growing Medium is Dutch brand TCM
Description - Google translated from dutch :
Growing substrate - Potting soil based on peat litter (white peat), garden peat (black peat), lava, grape seed cake
and 0.5 kg / m³ of compound fertilizer NPK 12-14-24 and 3.5 kg / m³ of compound organic fertilizer
NPK 7-7-10 with 43% organic matter whose nitrogen is completely organically bound; for use in
the most common plants [pH (water) zone: 5.0 - 6.5].
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4) Stage of growth - 36 days old plants
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5) PICTURE OF PLANTS

I'd be happy to take more pictures if it can help someone to identify the problem.