is this heater oK for SW?

[groan]

ijust realized it has an aluminium sheath around the heater and i remember soneone saying something against using metal parts in a SW tank...
http://www.bigalsonline.ca/BigAlsCA/ctl3664/cp18116/si1317025/cl0/aquariumsystemsvisithermstealthheater250watt

i got one at the BD sale and need to know if i should exchange it now before i use it.

[Faerin]

It'll be fine, I've got one in my tank as well and have had no problems. The outer coating is actually plastic with an aluminum shell inside, so there shouldn't be any metal contacting the water.