I think the fact they appear to jump is a give away their springtails, i always was told if it moves slow in the soil its bad, if it moves fast its good, springtails can certainly get around wheras root gnats etc are slow moving. Im sure im right, there are lots of types of springtails, even in the sea of all places, if they are they are harmless, even good for the soil. Good watering practices seem to keep the population under control. Thanks mind bender.