a chiller is a good thing because some people have temp swings more than 5 degrees a day
the temp isnt the problem it is how fast it gets up to that degree
The temperature in reef aquariums should be maintained between 22-27 'C (72-80 F) for the best results, and kept as stable as posible. In our experience, the center of this temperature range, 23-25 'C (74-78 F) is ideal. ... Marshall and Clode (2004) show a maximum calcification rate at 25 'C (77 F) for the corals Galaxea and Dendrophyllia ... . Other research shows the temperature of maximum calcification rate varies depending on the local normal temperature. ... In the natural setting, the most diverse coral reefs have water temperatures between 28 and 32 'C (82 and 87 F) for several months of the year. ... Our experience with aquariums has demonstrated that the temperature in a closed aquarium should not be maintained near the natural thermal tolerances of corals; on the contrary, it should be maintained significantly lower.
(Delbeek and Sprung, 2005)
Although it has been recommended in the past that aquarium temperatures should be maintained between 24-27 'C (75-80 F), the natural temperature of many Indo-Pacific reefs, especially in the shallow areas where most corals are colected, is higher than 27 'C (80 F).
It has always been assumed that temperatures at lower than normal levels prevented the unsightly algal films on the aquarium glass and lessened the proliferation of problem hair algae. Recent trends favor maintaining somewhat more natural reef temperatures of 27-29 'C (80-84 F). The reasoning behind this increase is that the entire metabolism of the tank is raised, including those of the microbial community, detritus-processing organisms, and herbivores.
...
Temperature (Min/Max./Ave.)
Average on all tested reefs ............. 21 'C (70 F) / 30 'C (86 F) / 28 'C (82 F)
Reef with lowest temperatures ........ 16 'C (61 F) / 28 'C (82 F) / 25 'C (77 F)
Reef with the highest temperatures .. 25 'C (77 F) / 34 'C (93 F) / 30 'C (86 F)
Borneman (2001)
