What Can This Be?

[deliverance]

i was just wondering ever since i started my first big tank i have noticed that there is a white powder(its hard to describe) which has been sticking to the rim of my tank, my HOB filters, my air pump and on my light. does anyone know what this is and what causes it. i can use a damp cloth to wipe it off. its getting annoying and i would like to get rid of it. i can take pictures if you would like.

 

[tidytourniquet]

Its just calcium deposits, its not harmful at all and I would just leave it. But if you want to get rid of it try some vinegar on the things that you can remove from the tank and a razor for the tank