Do shrimps eat surface biofilm? Is it bad if i don’t remove it?

I just added about 0.3 litters of ADA aqua soil into my 2 years old 2 gallon tank with 5 shrimp (i just added shrimps 1 month ago) because it only had gravel as substrate and I fear it might be too sterile and there aren’t enough nutrients to create biofilm

2 days later the surface is full of biofilm so i remove it. The next day it is full of surface biofilm again. I figured it would keep coming back. Can i just leave it as it is? Is it bad for my shrimps?