<a href=showthread.php?s=&postid=5089918#post5089918 target=_blank>Originally posted</a> by Walt Smith
Dear All,
It seems we are all at both ends of the field here. A couple of things to point out / remember. I am basing my comments on 16 years experience in the South Pacific (Tonga and Fiji) where the water temp for most of the year is mid 70's at 8 ft - 20 ft. where most of this stuff is collected. During our summer months, if we are unfortunate to get hit by hot spots (traceable on the NOAA maps from their site) the temp can reach into the low 90s and most of the coral dies or becomes bleached. In 1999 + 2000 season we lost over 90% of the entire coral reef on the eastern side of the Island and in most of the northern group (Yasawas) because of these hot spots which can be very discriminative with some reefs bleaching and less than a mile away everything is OK (or most of it) and there is really no telling where these spots will hit from year to year. Just last year I lost almost all of the corals on my farm racks spread over 7 different sites and while we monitored the temps bi-weekly some spots hit 92 (60 feet down) and others only hit 88. Still all died off. The racks we were able to move to much lower water had a higher success rate but some did still die. The racks we were not able to move had almost 100% mortality and the dance goes on from year to year as this now seems to be a regular annual occurring event. Dr. Bruce Carlson comes down almost every year to monitor some of the reefs he has labeled and we work together as he sees the same phenomena occurring while we all scratch our heads. It is because of his research and our daily observations that we are now beginning to understand more about the bleaching events that we can not control as we sadly just watch Mother Nature take its course.
Now, I'm just a dumb coral farmer and collector from Fiji and not a scientist but please consider these points.
I have seen a lot of reference to Caribbean temps. How many corals do you have in your tank from this region? None! How many species of Acro grow in this region? Few compared to Fiji and Tonga which is where most of the corals in your tank come from.
Fiji and Tonga are considered sub-tropical zones and you actually have to where a jacket in Tonga during the winter months and the water is freezing. I have spent up to 5 hours per day in this water and I usually come out blue.
If you have managed to acclimate the corals in your tank to the low 80's and they are doing fine then great I don't doubt this but please remember that you are skating on the edge with this temperature thing.
Your corals may grow faster but they have hollow legs and have accelerated growth leaving weaker structure. This may be acceptable in a home aquarium but reeks havoc on the reef as corals shoot up and break off under their own weight.
I have nothing to gain by telling you the truth about the water temps where I have worked and lived for the past 16 years but you can argue that 80 - 82 works best for you and if it does great. However, I do think that some of the references to stability are also important points to consider.
Will your corals die at 80 - 82 ¦ probably not. Is it the natural conditions at which they occur in nature ¦ defiantly not.
Keep in mind that the corals from Indonesia are a different matter where the water IS warmer but I still recommend mid to high 70's as a medium range to keep your mix well and happy.
Again, my opinions are just based on years of experience and I do not have any books to sell just friendly advice to offer.
Hope this helps clear a few things up or you can just take me out back and shoot me.
Forums like this are very good for sharing information and I hope you all do well with your captive reef at whatever temp works best for you.
Best to all,
Walt
