Soil condition

[Beowuuulf]

Hey guys

green Algee like substance forming on soil turning perlite greenish, hard to see.. is this harmless?
76 temp 55 RH. Exhaust fan and neg pressure in tent, leafs moving..

 

[MIMedGrower]

Plants only showing minor stress but it is a sign of watering too often. Letting the pots dry out more will likely resolve the issue.