Dirty Glass

[Kasakato]

I have just a used 10g tank from my friend. I has been sitting outside for about a year. I am planning to use this as my holding tank while I make the change from graval to _______. I know it can hold water because he has been water testing it for the last week. I was wiping the glass and notices some kind of white stain on the glass. I wiped it harder but that did nothing. So I took out my blade. I cut the stuff but only some of it come off What can I do to take it off? Will it affect my fish for the few hours they will be in there?

 

[ROLLIN]

You usually need to take this stuff off in layers. A good way to do it is to wipe it with bleach and water, then clean it with vinegar. Keep switching between the two until it is gone. Rinse extremely well after you are finished if you use bleach.