I'm plannin on buyin a 55 gallon from a guy tomorrow. I haven't seen the tank or talked to the guy myself, so I'm not quite sure what to expect. In any case....if it's got that crusty white residue on the glass or the rest of the tank, what have you guys found to be the best thing to clean it with/get it off? If I use any chemicals will they go away with cycling, or will it permanently alter the water? Like i said, i haven't seen it myself, so it might not be in that bad of shape. My uncle just mentioned the guy had said it just needs to be cleaned.....just gettin a heads up before i go tomorrow. Thanks.