little black pests in tank,used peppermint oil?

found some pests in my res the other day have had them before on a previous occassion and they help to collapse one of my plants roots.have searched and searched to identify what they are but still dont know.i know there too small for root aphids,anyway decided this time to just flush with a couple of drops of peppermint oil and teatree oil in mi tank and fingers crossed its culled um for now and culled um good.plants ok too.i also looked in every bucket i emptyed and not 1 alive in 60 liters.but anyone know or have any ideas what they might be plz feel free to post they look like minenute thrip looking things best i can do to describe um oh and there black.

You're going to have to do better than that. I don't know what a "minenute thrip" is. I don't know if its a fly or a maggot or a worm or a spider mite or a school bus. Pictures, or......some kind of description beyond color would seriously help. I mean really, you typed a whole paragraph and all I can take from it is "you have black pests on or in the vicinity of your plant's roots" You gotta admit, that's pretty bad.

yeah mate description prity bad but if anyone had bugs in there tank well they would have half an idea really obvious u havnt or dont so thanks for ur useless post??just as useless as my description eh?i havnt got a scope or a camera that will zoom so small.just know there little and erupt now and then in my res the pep oil working so not important i find out what they are now just thought if anyone else experienced pests in res tanks,if so at least i could have narrowed it down...........but im no pest expert and cant take a pic to post.just wanted to pick any other hydro gardeners brains sorry if the first post was useless to u obviously u havnt had pests in ur res eh or u might have been able to share ur experience instead of wantin pics,colour,size etc anyway like i said pep oil and tea tree controling um!sorry to sound like a bi ach but ur post as useless as mine mate!