why heat cold water ?
as most who have ever worked on a broken hot water heater knows, there is several inches of the nastiest foul smellingest mud in the bottom of almost all hot water heaters (that arent brand new). (an exception would be a on demand water heater that doesnt have a tank), but its still probably a good idea to filter and heat just to be safe. people who fix coffee by starting with hot water from the tap would most likely never do it again if they saw what was inside a hot water heater. i dont know what its chemical/ biological makeup is, but i cant imagine that it would be good for something as sensitive as a cham. most chams drink rainwater from remote areas so it just stands to reason that water heater sediment is not likely something is equipped to deal with. hot water is more recomended for sprayers than drippers because of the significant temp drop upon atomization. if one was to heat their dripper water it could concievably cause premature bacterial growth in the water. any heated water, (regardless of weather its a dripper or sprayer) should be changed at least every other day if it is not used up jmo