I picked up a 200 watt heater at a tag sale for $5. It has some strange rust on it, is this bad for the heater or fish? I have not put it in a tank yet but the owner said it ran fine...
agassizi;3210756; said:can you pick it off?
nc_nutcase;3210763; said:I highly doubt it's rust...
Is it on the inside of the glass?
In theory the inside of the thermoter is sealed and therefore anything inside of the glass will not be in contact with the tank. It's not uncommon for a little condensation to get inside the glass, but if an actual "exchange" of these two environments took place it would short out the heater...
But all that theory aside... is this a brand new heater? If so I would definitely contact the manufacturer and ask for a replacement. No need to take unnecessary risks.