Talk on Temps

[Carlo]

I'm going to go through some articles from "The Great Temperature Debate" http://www.reefs.org/library/article/reef_temperature.html and list some of them here that I think is worthy of reading. WARNING posts can be long.

Ron Shimek
The tank is reaching about 88 degrees in the apex of the lighting cycle. Last year ran about 82. It has fans on the sump as well as the top of the tank not to mention four computer fans in the canopy. I have done everything I can think of short of floating ice blocks in the sump. Animals don't seem any worse for wear so I am not exactly in a panic yet.

Given that they are just getting into the normal range for coral reefs (82-84 deg as average), I would suspect that instead of being in a panic, they are figuratively breathing a sigh of relief.

Do you see any harm in the tank approaching 88-89 degrees? I imagine that there are parts of the natural reef that go above and beyond these temperatures. I would venture to guess that these temperatures aren't maintained long term though
No harm. My tanks routinely will reach those temperatures in the summers. During two diving trips to Palau (richest coral diversity in the world....), one trip in April, one trip in September, the temperatures in the diving zone averaged about 89 degrees. Cool upwelling water measured 86 degrees, and hot water coming off the shallow lagoonal flats was about 95 deg.

What's your baseline temp? Do you run it at 85 degrees year round or step it up for the summer months to avoid massive temp swings?
My baseline is 84 deg.

Most natural reefs have massive temperature swings, though, on any scale you wish to measure, daily, monthly, annually, so that is not a big deal.

Based on that information I guess I will leave well enough alone. At what temperature do you think one might begin to see problems?

I would worry about prolonged (several days- couple of weeks) temperatures above 90 deg. One thing, if your system has been normally kept at 82-84, the organisms in it will be a lot more tolerant of the higher temperatures than if they have been kept in the cold (75-80).

With that in mind, my tank is beginning to reach 85 degrees during the day and about 84 at night. How large do temperature fluctuations need to be before it becomes detrimental to reef inhabitants?

Fluctuations are really not a problem - in some higher latitudinal reefs the fluctuations are enormous. There are data from Johnson Atoll, showing fluctuations on the order of 20 deg F in a single day (from about 72 deg to about 92 deg), and guess what... The reef's still alive...

What is more important are the extremes and the duration of the extreme values. Temperatures over 90 for any extended period is a problem, particularly for corals normally kept at cooler temperatures. I would watch the temperatures and attempt to control the environment so that temps over 90 are avoided.

 

[Carlo]

Ron Shimek
However, for corals from high temperature areas (particularly the Palau- Malay Peninsula-New Guinea are that accounts for over 70 percent of the coral species) this lower metabolism generally also leads to death...
Consider if these corals could tolerate lower temperatures in nature, they be living in areas that had the lower temperatures.

Bob,
So if an animal is collected from water in the 74-78 degree range(typical for collection areas in Fiji) are we slowly killing it by subjecting it to mid 80 degree temps with the resulting higher metabolism?

No, those animals found in fringing areas, outside the center of the distributions (what is called the center of adaptive radiation) have a wider range of tolerances - in this case temperature tolerances - and can survive in the outer areas. These animals will generally do better at the conditions at the center of the range, in this case, temperature. So if you collect an animal from Fiji or the Florida keys, and keep it at the temperature of the richest appropriate reefs (for example Palau and Belize) respectively, the animal will do better as it will be living under its optimal conditions.

With all of the scientific data about coral reef water temps that climb even into the low 90's, do we know how many of these studies were done in the same areas as coral or fish collecting is done? It would seem like a rather significant point to consider.
The data from temperatures and coral diversity I used in my article come from studies that pretty much predate the reef hobby and the recent period of global warming. I did not use data from these correlations that were collected after about 1975-1980. In other words, collecting influences and recent warming events are immaterial to the argument. To determine the appropriate conditions for most of our corals, take a look at Veron's book (for example), take a look at the range maps shown, and superimpose those maps on the maps of global coral diversity. Use the conditions at the center of that data.

Individual temperatures at the edge of the ranges are immaterial. Corals disperse rather well and over a few hundred to a few thousand years, the larvae can island-hop to all the places where the coral can SURVIVE. Relatively few of these places are places where the coral can THRIVE. Typically the organisms from the outer reaches are growing very slowly (too cold) and not successfully reproducing (as there are no downstream habitats that are successful). The net result of this is that they are genetic dead-ends and will not contribute to any changes in the gene pool. Basically they are space fillers.

Most corals simply cannot naturally survive out of areas where the temperatures are less than 80 deg as an average, and the number of species can be found in these areas is significantly lower than those in the centers of the ranges. The moral of the story... If you want to see what a coral reef can really look like, go to the reefs within the center of the area of adaptive radiation. High latitude reefs (most of the GBR, by the way) have many fewer species and reduced communities overall.

 

[Carlo]

Ron Shimek
Hi Bob,
My concern is the belief that mid 80 degree temps are desirable.

Yup. All those corals in the Indo-Pacific reefs must be suffering tremendously.

Granted, our captive reefs can and will tolerate these temps, but I'm not so sure that steady maintenance at say 85 or 86 degrees is a good thing.

First, nobody is saying to keep anything at 85 or 86. I recommend 82-84 degrees. The animals will do as well at 85 and 86 as they will at about 80-82.

That species of coral has adapted to the temps it was collected in over many generations.

Wrong. You don't know where the coral's parents were from. The larvae come from upstream spawners, and given the currents prevaling in most of these area, the general flow is from warmer areas to cooler. If you are collecting an animal that has asexually reproduced by fragmentation for several hundred years even, you are still seeing only one generation.

You are discussing physiological accomodation to temperature, not evolutionary adaptation. Really the only coral that has been shown to have a decent growth rate at about 78 is Pocillopora damicornis. However, it has a second growth optimum at 84 degrees.

Just because diversity is better at higher temps doesn't mean the coral is going to like it.

Animals are found where they can live. Simply put, coral survival has been 1) correlated to temperature (i. e. = higher temps give conditions that allow more species of corals to survive, and 2) experimentally shown to survive better at the higher temperatures characteristic of the diverse reefs, and 3) experimentlally shown to have growth optima 82-84 degrees.

The idea is just flawed from a simple logic standpoint, at least in my mind. I mean, you don't collect an animal from the temperate waters of California and expect it to live at tropical temperatures of our reef tanks. How and where does one draw the line at what sort of temp adaptation the coral can handle?

Look at where the species is found in nature... If most species of corals are found living at areas that average about 84 deg F, and if most of these species grow best at those temperatures, it rather follows that if you want those species to be healthy, you maintain them at those temperatures.

, it was found that the holding systems at the collection station need to be run 2-4 degrees cooler in order for the animals to look their best. They just don't open up as well when maintained at the same temps found on the reef. Why is anyone's guess, but this is an observation made over years of collecting and not just some gut feeling.

I would guess that they are 1) stressed from the movement into the holding systems, and 2) the holding systems have something in the plumbing that effects the animals in the facility. Similar problems are occasionally encountered at marine laboratories, and the most common problem is alteration of food supply due an increased amount of suspension feeders in the plumbing. But the stress factors of collection and handling are likely also great. Also keeping animals at about 2-4 degrees cooler than normal, will reduce their metabolism to a point where they can get by on less - albeit the tradeoff is that it makes them less able to handle stresses.

 

[Carlo]

Eric Borneman
I was not following this thread, until I saw esteemed James post a summary which piqued my interest. I take it this had to do with the fabled "ideal" once again. Without having having the full thread, but knowing from experience what these things entail and some views of some of the participants, allow me to put forth my ecological/biological viewpoint, if I may.

I suspect Ron was stating the positive attributes and tolerance of animals to higher and varying temperatures. I think it amazing enough that in five years, hobbyists have gone from believing 76 was ideal to about 80. I personally run my tanks even higher - 84. But as James stated, no one has done any real measurements, to my knowledge. However, what good what it do? The assumption of this is that animals, collected from various locales, various depths, various reef zones, all have some ideal temperature. This is lunacy. Our animals are collected from areas where 76 and 90 can both be "ideal", so to speak.

Now, Ron's general view of increased metabolism and greater growth is biologically sound to a certain limit. There is an upper and lower limit, and it is based on an almost case by case basis. Furthermore, temperature interacts with a number of other variables, including irradiance, UV, nutrient loading, degrees of competition, etc. There is are many excellent studies discussing the interactions and effects of temperature on coral reefs and coral reef biota. I'd be happy to provide some to those interested.

Be all that as it may, coral reefs are one of the most temperature sensitive biomes on Earth. It doesn't take a rocket scientist to read headlines about increased sea surface temperatures and all the bleaching (which, btw, caused 75-90% mortality over many reefs last year, even in the "bleaching proof" Pacific reefs). The bleaching has been linked almost entirely to the warm waters which, fwiw, were in many cases significantly below what would be considered an upper thermal limit for others and in some cases lower than what we keep our quaria set. The thing is, corals live within a few degres C of their upper limits even under "ideal" conditions. This is long term, not short term. There are many which live in areas which are exposed to sometimes huge hourly or seasonal variances in T - the Gulf of Oman is especially studied in this regard. Some of the Red Sea areas get blasts of cold air that can chill exposed corals down to 50F and then later on, they are regularly bathed in 90F + water. There have been studies to examine this phenomena, and transplanted corals usually do not live. It appears that corals from these areas (and lagoons, tide pools, etc.) are specifically suited and tolerant of such temperatures. Same with some of the high latitude reefs where water temperatures get quite low. This should be obvious as the diversity of species in such areas is always less.

OK, that said, where does that leave us with our tanks? Once again, we don't know the location where animals were collected. Likely, most are coming from easy-to-collect areas where it is shallow and probably subject to some degree of temperature variation on a daily or hourly basis. Thus, our animals are probably quite suited to a variation in temps, all of which may be seen as the range of "ideal." Certainly we know that deep water animals will not be exposed to as much variation, and likely less upper thermal stress, although cool upwellings may make them more tolerant tolower thermal levels.

Our tanks are not ideal in many ways, and therefore pushing the upper limit is, imo, a little risky, given the interaction of variables. However, the repurcussions of keeping tansk at lower temps that are probably near the lower limits of collected animals, and also in terms of the productivity and reproduction of the community, is probably equally detrimental. I don't think 84 is pushing the upper limit for most reef corals, although 86-88 might be. Heliopora, otoh, will love it. In terms of those who see problems at 76 or 86, then address it. To say that a tank runs better at 82 v 80 or 82 v 84 is pretty much ridiculous. There is rarely, if ever, that kind of thermal stability anywhere and effects of 1C or less, if it exists, is probably being primarily caused by conditions other than temperature.

Anyway, that's my posturing, fwiw.

 

[Carlo]

No more. They were the ones I personally found interesting. The whole archive is available at http://www.reefs.org/library/article/reef_temperature.html for your reading pleasure if you are so inclined.

I wanted to capture Ron's thoughts on the spawning like:
"The larvae come from upstream spawners, and given the currents prevailing in most of these area, the general flow is from warmer areas to cooler. If you are collecting an animal that has asexually reproduced by fragmentation for several hundred years even, you are still seeing only one generation."

but some of those posts were really long. Basically he implies that areas like Fiji get seeded from warmer areas and the corals in Fiji would prefer warmer temps.

I'm not saying I agree or not with any of this but thought I'd share some of it for those interested in temps on the higher side. There are quite a few opposing views from others on the list I might add.

The one constant I'm finding is the more research I'm doing on temps the more other industry experts seem to be saying higher temps are OK or better for the corals.

Carlo

 

[ricwilli]

What a coincident that this thread was posted. I came home today and the tank temp was 86 degree. I started freaking out. I pumped up the AC as well as put a fan on the sump. Reading this thread has me a little confused on what is the ideal temp. For what its worth, all my corals looked very very happy at 86. All the corals were blooming. Now the temp is at 82 degree.

 

[Hawkeye]

Thanks for the post Carlo - it was a little hard to read because I wasn't always sure if Ron was talking in italics or not...lol.

The post just reinforces my own feelings of complete and total inadequacy when it comes to really understanding our reefs.

I would submit though that the actual "temperature" is less critical (though still important) than maintaining a stable range.

While one can grab a NOAA satellite pic to show that the Gulf of mexico ranges from 70~mid 80s, we don't want those kinds of temps in one day in our tank.

 

[Phyl]

As far as temps, I think you'll find as many opinions as... ears in the club. On my sps/lps reef I'm more finicky about keeping the temp right at 80. Fans go on if it gets over 80.5, heaters go on below 79.5, blah blah blah.

On my softie/mushroom/whatever tank the temps frequently hit 84 and I don't really sweat it much.

I agree, Phil. I'm sure that the temps anywhere on the reef aren't swinging 3-5 in a day. Keeping that to a min is probably more helpful than making sure we're pinned to any given number overall. *




* This is based purely on my opinion.

 

[blange3]

This reinforces my concerns over looking at single parameters outside of the context of a full system.

I would be real concerned cranking my system up from a very tightly controlled 77.2 to 88. I'm sure I would incur losses:

A)because of the conditioning of my corals.

B)because it is a closed system with lots of non optimum things that I don't even suspect help corals in a natural reef environment tolerate the spikes.

I guess philosophically speaking I believe I can only emulate a reef in a 75 gallon tank, not duplicate it. And someone like Carlo may come closer because of his vast volume of water, but the natural reef will never be exactly duplicated. Therefore there will always be a need to maintain certain levels other than I would find on a reef.

Addressing Ron Shimek's quote on growth, I can show photograhic proof that corals do show decent growth at 77. Brian posted some pix of my tank a little over a year ago showing a pinky size milli frag. I've been meaning to take a current picture to do a before and after comparison as that frag is now a decent size small colony. All along the temp has been controlled by an ACJR that turns the heaters on when temp drops below 77 and off when they exceed 77.4. Lighting during the summer may kick it up to 78.4. I start shutting things off at 80, but that has never happened. The tanks are in the basement which stays pretty stable temp wise.

 

[Carlo]

What a coincident that this thread was posted. I came home today and the tank temp was 86 degree. I started freaking out. I pumped up the AC as well as put a fan on the sump. Reading this thread has me a little confused on what is the ideal temp. For what its worth, all my corals looked very very happy at 86. All the corals were blooming. Now the temp is at 82 degree.

I myself haven't really experienced problems at this temp but do know of others who have. Short durations into the 86 mark IMHO don't do much even to Acros but keep it short at the higher temps. Of course every system is different. I think IMHO the biggest thing is people who keep the tank nailed at a certain temp experience much more problems when all of a sudden the temp hits 86 as the corals aren't used to adapting (as much) to that temp. While the tank that normally fluctuations a couple of degrees each day and ran in the 82-84 range normally is used to shifts in temp and can handle it better. This is my theory but there seems to be data out there to back it up.

Carlo

 

[Carlo]

phil519, I agree with you. I think a stable "range" is more important too then a nailed down specific temperature. Just my opinion however.

Phyl, I agree with you too that there are lots of opinions on temps. I also want to try and find some other articles to post that give good reason to keep things at 80 or below. I'm not trying to sway one way or another. I'd like to try and show many views on the subject. Pretty much most people know how I run my system if they've read a handful of my posts.

So while I'm not trying to "prove" anything I'd like to try and get/show opinions of many people in the field especially those of biologists and those doing experiments with data (harder to find).

I do disagree on the 3-5 temp difference on the reef however. Just about anything I've read and from my own diving experiences at different reefs tell me 5 degree shifts in a day are very common. But I don't think that should translate to letting our systems fluctuation 5 degrees from our baseline in any direction. Maybe 2 degrees on either side of the baseline for example 82 baseline, heater set at 80, chiller/fan at 84 or something like that, maybe slightly more narrow like 82 base, 80.5 heater, 83 chiller depending on how long it takes for the heater/chiller/fans to kick in and do there things. Just my opinion however.

blange3, I'm sure you would incur losses to doing that. However if you were to want to switch to higher temps you would probably want to slowly work up to that range. For example slowly increase the average temp say .25 degrees every couple of days so there is only a 1 to 1.5 degree shift per week. Maybe even a little slower then that. Then as your slowly work up in the temp range slowly add a range into into by adjusting heater/chiller slowly from the baseline. Slow and easy. Again keep in mind if your system is running great at the temps you are using then maybe you don't want to adjust anything.

IMHO I think most people can get by with a vast range of set temps. If your temps run on the high side naturally then go with something in this range. If you run in a basement and run on the cooler side then go with that. By using what you got so to speak you can save massive $ on electricity and chiller/heaters trying to fight heat/cold instead of letting it work for you and adjusting your system around those temps.

We know people can keep all kinds of stuff from mid/high 70s to mid/low 80s very successfully. See where I'm going with this?

Carlo

 

[Subliminal]

I don't know about the corals, but when my tank gets to the mid 80s, nuisance algae sure does a lot better in my tank.

 

[Carlo]

Everything can do better at higher temps because the metabolism is higher. That just means you need to work harder to keep nutrients low.

Never said it was easier.

Carlo

 

[blange3]

Everything can do better at higher temps because the metabolism is higher. That just means you need to work harder to keep nutrients low.

Never said it was easier.

Carlo

There's another reason why I approach temp the way I do! Easier is better for me.

And another reason why the reef is more tolerant of high temps than a small tank is, much better nutrient control on the reef.

 

[Carlo]

Amen to the nutrient control blange3!

 

[Boomer]

Carlo

I did not read all that and probably wont' it is not my cup of tea so to speak. Ron also has an article in either ReefKeeeping or Advancedaquarist and I think it is the later. You should also have posted a link to Eric's quotes but it is not need IMHO, as you have his name there but there maybe diagrams in that article, don't remember. Also, in Ron's article and for others reading this, please pay no attention to that Salinity vs Sg table it is way off or us. It is set to 20 C, a soils hydrometer and we are set to 25 C

 

[Carlo]

Boomer,

I'm actually trying to find articles on different temps for tanks with pro/cons, etc and different points of view. Doesn't matter if it's geared towards higher or lower temps. No bias either way in the thread.

Just looking for different perspectives and whatnot. If you have any links handy to list here go for it or cut & paste is fine too.

Thanks,
Carlo

 

[Boomer]

There are probably crap loads, posts, of them on RC or RF. You might also want to check Bomber's forum The Reef Tank. I'm not into temp' s really at all. I do not know of any articles other than those mentioned. You may want to do a search on Reefkeeping, Advancedaquarist or the files on reefs.org.

 

[Carlo]

Here's another article from Ron Shimek on Reef Stability I thought I'd share. It's the same mentality as the earlier posts but "more together" since it's an article and not from a mailing list.

http://www.reefland.com/rho/1105/reefc7.php

The article talks about both Temp & Salinity.

Carlo