Powdery Residue in my grow room!?!?!?

[Natures Cure]

Can anyone tell me anything about this powder shit, is it just from my cool mist humidifier or is it going to pose a problem?

 

[the75bag]

big problem anything above 50% humidity is bad for flowering looks like your running at a constant 85-90 get that thing out with all the plants and bleach the walls 3 times in 1 week with water and bleach mix

 

[Natures Cure]

big problem anything above 50% humidity is bad for flowering looks like your running at a constant 85-90 get that thing out with all the plants and bleach the walls 3 times in 1 week with water and bleach mix

The fucked up part is that my humidity stays right around 30% and I have to run the humidi all the time just to stay around 30% otherwise I can't get my humidity above 20%. Is 20% ok (I'm sure it's not) and is there a better way to add humidify your grow room?

Are we sure that since the humidity stays around 30% that the residue isn't just salt, minierals, etc.?