[Adam]

Rafa,

Sorry to get off topic. IMO, your corals will do great if you maintain them anywhere in the 76 to 84 range as long as you avoid big swings.

Saltshop,

Have you read the literature for yourself? Alot of others have, and have a different interpretation.

Your right, sorry for my semantic error. Growth in many species(until you reach an upper thermal limit) is greater at higher temps.

On the issue of sudden vs. sustained temp rises... Again forgive my semantics. The less the temp rise, the longer it takes to induce bleaching, but more than a couple of degrees can cause bleaching in just a few days.

As far as pathogens.... Human physiology is adapted to a regulated temp, corals are adapted to handle the temp range they are normally subjected to. Of course I am not suggesting that pathogens will suddenly go into overdrive at higher temps, but what basis do you have to suggest that corals will be immuno-supressed at lower temps?

Our tanks..... I agree with everything you said, but how many aquarists do you know that maintain normal or lower than normal stocking levels compared to natural reefs with any true bulk water flow???? Keep in mind the billions of gallons that ebb and flow every tide! Do you surge hundreds of gallons of fresh clean water through your system daily? I sure don't!

Coral growth in captive systems has been documented to be equal (and even greater) than in the wild. This data is several years old, when pretty much no one maintained a reef tank above 80.

As far as Veron's books are concerned... I won't speak about the exact statements made, but in Corals of the World, alot of factors affecting maximum diversity are discussed. Temperature is one, but sunlight and geographical features are also important. If temp is the major factor, why is diversity so much less in the tropical atlantic? It is just as warm as the indo pacific, right? It is because the near surface geological structures aren't there for the corals to grow on. Also, why is diversity not the highest in the Red Sea? It gets warmer there than the central Indo Pacific.

My major problem with this whole debat is that beginners aren't getting the whole story. IMO, telling beginners to maintain reef tanks in the mid 80's is irresonsible. Until one has the experience to know how to recognize and handle problems with their tank, they can use every bit of safety margin they can get. I have been doing this for many years, and I recently had significant losses due to a chiller failure. If my tank had been 84 degrees to begin with, I am absolutely sure I would have had nearly 100% mortality in my tank.

The argument that corals are somehow slowly dying at temps below 80-84 just doesn't hold water. Many aquarists (myself included) have watched a wide variety of corals grow very quickly at temps in the 78 degree range. Why would an animal fighting for it's very life waste energy on growth?

While I am on a rant here..... Even if you do believe that the average (over several years) temperature of all the reefs is 82, how long has it been that way in evolutionary terms?? The data is sketchy for surface seawater temps when you go back more than a few years, but we know that average global temps are up in recent years, so wouldn't it follow that near surface sea water temps would be also. This interestingly corresponds to the increase in bleaching events in the last few years.

The temp in Fiji is too cold for the survival of what??? Sure Fiji may not be a the center of maximum diversity, but it is still quite high. Get out your Veron books, and see what the diversity is in southern Japan, which gets much cooler than the 77 degrees you state as the coldest reef known. It certainly is less than the central indo-pacific, but it is much greater than the tropical east atlantic!

I have a great deal of respect for Dr. Ron in terms of his knowledge of invertabrate biology, and I especially appreciate the time he devotes to the hobby. I happen to respectfully disagree that 82-84 degrees is the ideal temperature for everyone to maintain their reef tank at, even if it is the average temperature on the wild reefs. As hard as we try, we will always have alot of animals crammed into a small body of water, and that demands certain compromises. With experience and top notch husbandry, those temps may be fine, and may even be desireable, but it isn't for everyone or every tank.

I'm done now, and won't post any more in this tread. I just want to make sure that everyone (beginners in particular) know that there are valid arguments for both sides, and that they shouldn't make any choice for their system without knowing the ramifications.

Adam