I'd use Nematodes, and Diatomaceous Earth to get rid of them if it were me. If that didn't work(but I'm sure it would) , then I'd use General Hydroponics Exile as a last resort.Theres literally thousands of them just on the surface of the soil and rim of the pot. Its pretty bad.

I have seen some people don’t mix peat and coco when making their own soil and I’ve only used Coast of Maine Stonington blend which is a mix of peat and coco? Also only use RO or rainwater