Are these root-aphids? I can't identify them. [pictures]

Hey there,
I found these little buggers on the coco-/soil plugs of my clones.
They weren't many, but every once in a while, I found a few.

For at least two weeks I sprayed them with a combined lice-/mite contact pesticide every 3 days and it didn't seem to bother them too much.
Keeping the clones a little dryer seemed to help though.


Fast forward some weeks, and the clones are flowering in a RDWC bucket system.
A few plants show slight problems with older mid-leafs beeing spotted and getting yellow tips.
Probably pH-/calcium troubles, but I inspected the roots to be safe.
While they do look relatively good, I found a lot little crawlers.


They are about 20-40 Thou (0.5-1 millimeter) big.
Even on very close inspection I couldn't find a single mite/aphid or anything on the green plant. neither on/under the leaves, the stem, or around the buckets.
It seems like they are just inside the buckets.
Water temperature is 68F, room temperature is 75F at day and about 67F at night. Humidity is around 35 - 50% rH.



Any ideas what they might be?


Taken from a clone (seemingly they ate something green?)





Same individual:



Dead individual from a RDWC bucket:




Closer View:







Many thanks in advance!

i think that is not an aphid. it has eight legs and doesn't have the tailpipes that aphids have. theres composting mites that you find in soil sometimes when there's been overwatering. you can find them in coco as well as soil but i've never seen anyone have them in a RDWC system. they are decomposer bugs and eat brown roots. you mentioned that when the clones are a little dryer, it's not as bad. try watering less with the clones and i have no idea about your rdwc but maybe more circulation or air? definitely not an aphid. they'll leave when you fix the environmental problem that lets them thrive.