Is it just me or is that two different critters?
The top photo has a distinct mite/tick shape the head and body are individual so to speak, the bottom photo are springtails, they've a more elongated body, their head is in line with the body?
They're best left alone they only eat dead and decaying matter and shit out fertilizer lol.
If you want to stop seeing them in tanks/reservoir/dwc use some wetting agent and they sink and drown, the wetting agent takes away the surface tension they depend on.
Lots of insects can trap a bubble with the hairs around them, wetting agents also fucks that up, it's not important with springtails but imo certainly for any real pest, a touch of soap/detergent works but wouldn't be my 1st choice.