the power usage will depend on temp and needed drop. but considering what we have invested in our tanks,,i dont mind the usage. with pumps and lights and room temp,,i need my chiller.
as for used...see it in action,,,caveat emptor
as a bulb gets used the phosphurs burn and as they do they degrade. this causes a shift in spectum. its not creating matter is a rearrangement so t speak. as a bulb ages the spectrum will shift from the shortwavelengths to longer ones (blue to red) nuisience algaes will thrive in a more...
from what i have seen, dragons are an invert hunter, looking for tasty shrimp and other small creatures to eat, that is why they flip rocks and move sand around. my main concern would be a clam on or near sand might fet buried while the dragon forages for critters.
boiling the rock will only get rid of the algae on it,,it the rock has a sufficient P level it will grow back...cooking the rock or letting the algae consume it is the only way to reduce locked levels. hebivores are grat for keeping algae in check as long as removal of their waste is done, or...
butterlies are clam eaters,,its possible it had been picking on it without notice,,,their skinny mouth can get inside of them. and it started to die and the crabs got it.
look in the manual for custom setting/WB. that way you can have it saved and use it when taking tank pics,,,use cam for other stuff,,then come back and not have to reset it.