Mold on basil plant soil?

My first pods (basil) have been growing a layer of what looks like mold on the soil. I’ve removed it a couple of times and it keeps growing. Currently 2 of them (picture above) have a lot of it but otherwise the plants look healthy and have been growing lots. Looking for advise on what it is and if it is harmful!

Thanks!!

Mold is normal and does not affect the plants. There is some information about it on official C&G website: https://support.clickandgrow.com/hc/en-us/articles/360000947227-19-How-to-get-rid-of-mold-and-algae-