Ell,
I would recommend buying another good quality heater for two reasons:
1) You need to bring the new saltwater to tank temperature to check salinity and a heater is the only way to conveniently do this. Certainly any cheap heater will do this chore.
2) More importantly, during cold weather, the major risk to your tank is a big drop in water temperature. Though Ebo's are very good heaters, (I have 7 of them) like all mechanical devices they can fail and a spare may save your tank.
An Ebo or Visi-Therm 100w should be less than $20, mail order.
HTH
Dick
