spider web slime coat after water change?

[MagicalAlpha]

I got two CRS dropped on me today so I just did a quick 30% water change with RO water and added some prime as well. But shortly after that I starting to see all these white slime/spider web forming on my moss...I have had this from my other tank before they normally go away from like few hours.

My tank parameter prior to water change
pH 6.8
GH 4
KH 0
TDS 151
nitrite and ammonia 0
nitrate 20
Temp 72

new ada amazonia