White Crystals Near Filter And Tank

[Lola&Spike]

On the outside of my 47 gal tank these white clumps of almost like... crystal like forms are showing? They don't give off a smell or anything from what I've noticed, and are not having any effect on my fish in the tank. The crystals are on the outside of the tank, especially around the filter, and some at the bottom on the stand the tank is on. They are like white clumps of crystals. Just curious if they are harmful or not, what they are, and what they're from?

 

[StevenF]

Most likely you have a small possibly intermittent leak.  The white material is minerals  that were in the water before it evaporated.  The white material is not hazardous but the source of the water should be found and repaired.  The other possibility is some water was spilled in the past  and evaporated and the white material was left behind.