Acceptable Daily Temperature fluctuations

[sandgoby]

Hello,
I have been in the process of programming my Apex over the past several weeks. I have been struggling a bit with the temperature. I really only want to have the chiller come on as a safety. I have 2 independently controlled series of fans on my setup. The set points are as follows:

Hood fans 1
If Temp > 78.7 Then ON
If Temp < 78.5 Then OFF
Hood fans 2 and sump fan
Fallback OFF
If Temp > 78.8 Then ON
If Temp < 78.6 Then OFF
Chiller
If Temp > 79.1 Then ON
If Temp < 78.8 Then OFF

So the question is what is an acceptable temperature variance during the course of a day as to not stress the corals and fish?

Thanks.
S

[chuckreef]

three to four degrees is OK.
There is no chiller or temp. controller out there that can accurately do a 0.3 degree cycle despite your ability to program your Apex that way.

I'd simplify to one degree inside bracket fans and two degrees outside bracket fans, and with the chiller coming on at 81 or 82 (" really only want to have the chiller come on as a safety")

[sandgoby]

Originally Posted by chuckreef

three to four degrees is OK.
There is no chiller or temp. controller out there that can accurately do a 0.3 degree cycle despite your ability to program your Apex that way.

I'd simplify to one degree inside bracket fans and two degrees outside bracket fans, and with the chiller coming on at 81 or 82 (" really only want to have the chiller come on as a safety")

So if the temp bobs up and down a full degree or slighty more it's ok? I was freaking out over a 0.8 variance over the course of a day?

[Amphiprion]

I'll go so far as to say that there isn't necessarily a generalized range at all. My older reefs would potentially swing as much as 6-7*F daily, especially in the summer--all without any apparent issues. Was that necessarily ideal? Not likely, but not life-threatening, either. Really, there are too many variables to even give a safe range. One thing I can say, however, is that I think this variance kept corals resistant to even larger swings. FWIW, I kept an average on my systems at around 82*F, with peaks/dips in respective measures. That is one reason why I think it may be unnecessary, if not a bit wasteful to have a chiller "kick in" at around 82 degrees.

[flyyyguy]

Originally Posted by sandgoby

So if the temp bobs up and down a full degree or slighty more it's ok?

its not only ok, I dont think its a good idea to even try to keep it at exactly the same temp all day long

swinging your temp some makes your corals much more resilient especially when the inevitable swing does occur, or if you trade and ship any of them very often they will fare much better

I use chillers and controllers and swing all of my systems 4 degrees or so daily and they are mostly sps

It doesnt even phase them if they are used to it. Besides, 6 degrees+ isnt an uncommon swing on many wild reefs

Just last week I tested this theory a little more severely than I would like to have. The door to my fishroom blew open in a high windstorm in the middle of the night. Didnt have it latched well or something. The sps tank right next to the door was 72 degrees when I woke up. I usually keep it 78/79-82. All corals had full polyp extension and it was like like nothing ever happened. I guarantee that if that were to happen in a loaded sps tank that was kept within 1 degree all of the time, there would have been some ticked off corals

[sandgoby]

Originally Posted by flyyyguy

its not only ok, I dont think its a good idea to even try to keep it at exactly the same temp all day long

swinging your temp some makes your corals much more resilient especially when the inevitable swing does occur, or if you trade and ship any of them very often they will fare much better

I use chillers and controllers and swing all of my systems 4 degrees or so daily and they are mostly sps

It doesnt even phase them if they are used to it. Besides, 6 degrees+ isnt an uncommon swing on many wild reefs

Just last week I tested this theory a little more severely than I would like to have. The door to my fishroom blew open in a high windstorm in the middle of the night. Didnt have it latched well or something. The sps tank right next to the door was 72 degrees when I woke up. I usually keep it 78/79-82. All corals had full polyp extension and it was like like nothing ever happened. I guarantee that if that were to happen in a loaded sps tank that was kept within 1 degree all of the time, there would have been some ticked off corals

OK now I am a little confused. According to the Reef Aquarium Volume 1 Chapter 8 under water quality parameters. It states that water temperature should be as stable as possible. Plus or minus 1 or 2 degrees is acceptable. More so for the health of fish. Wide fluctuations are associated with incidences of "ich".
But I guess my question was not posed very well to begin with. With my addition of the Apex (which may to a little to much info for my own health ) I noticed that my temps before were about 79.5 during the night (Lights off) and reached a peak of 80.6 during the day. No big deal right? That said when tracking the temp over the course of the day my temp would clime to 80.6 over the course of about an hour and then drop to 79.5 in about 10 min when the chiller came on. This happened about about 6 or 7 times during the day. My attempt was to stabilize the temperature so that these dips during the day would not happen as I believed they were stressing the fish and some of the corals. I could program the Apex to simulate a gradual increase in temperature of 1 or 2 degrees after lights on to lets say noon and then start to drop the temperature down to what it should be at night.
My attempt is to reproduce the temperature variations of the natural reef as closely as possible.
Has anyone else had experienced these frequent dips in temperature using a chiller? And would this be detrimental to the tank inhabitants? Not to mention I would like to stop using the chiller altogether, as the bloody thing uses about 7 amps when it's on.
Thanks for your input!
S

[jimsplace]

I don't have a heater or chiller on my tank. The tank pretty much stays around room temp, but climbs about 2 degrees during the lighting period. Winter temps are always lower and summer higher. Tracking the temps on my apex through out a week, lows to highs may vary several degrees depending on the weather outside, but the daily fluctuations are rarely over 2-3 degrees.

[frankpayne32]

IMO/E chillers are an unnecessary expense both in terms of initial purchase and electrical usage. in most circumstances. Like others have already said fluctuations are natural on wild reefs as long as they don't happen quickly and are not in the double digits. If your tank gets really warm in the summer I would try cooling fans set on your Apex. It's amazing just how well evaporative cooling works. This will use much less electricity.

[wet reefer]

IMO, Flyyyguy got it right. My tanks fluctuate a couple degrees daily. Anybody who has been diving enough or even snorkeling feels these fluctuations. Iv'e dived in places where the temp was 3-4 degrees different on the same reef from one day to the next or even morning to evening depending on the tides and the currents associated with them.

[RenoR1]

I have a regular temp flux of 2-4 degree depending on house temp and time of day. It is somewhat natural. When the sun goes down on a reef the surface temp will drop. Thats just how it works. As long as none of your stock is showing any signs of being affected by the change, your okay.

[greenbean36191]

According to the Reef Aquarium Volume 1 Chapter 8 under water quality parameters. It states that water temperature should be as stable as possible. Plus or minus 1 or 2 degrees is acceptable. More so for the health of fish. Wide fluctuations are associated with incidences of "ich".

There is no evidence to support this assertion. It's simply inferred from a study done on FW fish in a production pond- salmon IIRC, which are stenothermal.

However, reef fish have evolved in a rapidly fluctuating environment where a range smaller than 2 degrees would be pretty unusual. Therefore you would expect that they would do just fine with larger variations. And in fact, no one has thus far shown any correlation between temperature fluctuation and disease prevalence or any other stress indicator such as respiration rate or stress enzymes in reef fish.

For corals, studies have shown that fluctuating temperatures improve the photosynthetic efficiency of corals and improve their resistance to bleaching and disease outbreaks due to unusually high temperatures. There is no evidence that fluctuations are stressful to them. It's only when temperature exceed the maximum temperature they have been acclimatized to that stress begins.

I could program the Apex to simulate a gradual increase in temperature of 1 or 2 degrees after lights on to lets say noon and then start to drop the temperature down to what it should be at night.
My attempt is to reproduce the temperature variations of the natural reef as closely as possible.

This doesn't reproduce the temperature variation of the natural reef at all. The pattern you have happening in the tank now is much more natural, though the magnitude of variation is much smaller than on most reefs.

The natural variation is driven primarily by mixing of different water masses, not by diurnal heating. As a result it's characterized by short, quick changes of a few degrees and that last from a few minutes to a couple of hours, not by gradual rises and falls. On a typical reef, the minute-to-minute variation has been documented to be about half of the annual range.

To give you an idea of the types of changes that can occur, there have been cases where changes of about 9 degrees F have been documented to occur more than 10 times within the course of 3 hours without any apparent harm to the corals or other inhabitants of the reef.

[m2434]

A lot of advise in this hobby is based on assumptions. Research is showing corals adapt to temp swings and further, temp swings are beneficial.

Here is one summary of a lot of the research out there. I have read a number of the original articles referenced and they seem to be good science. I've also run farily large temp swings myself for many years without issue.
http://www.co2science.org/subject/c/...chresptemp.php

[sandgoby]

Originally Posted by m2434

A lot of advise in this hobby is based on assumptions. Research is showing corals adapt to temp swings and further, temp swings are beneficial.

Here is one summary of a lot of the research out there. I have read a number of the original articles referenced and they seem to be good science. I've also run farily large temp swings myself for many years without issue.
http://www.co2science.org/subject/c/...chresptemp.php

Interesting article. So we know that corals as a whole are highly adaptable to temp variations (within reason). My attempt as I am sure that all of us in the hobby is to create the best conditions for my tank. We all agree that some daily temp variation is good for our tanks and that the variations need not be due to heating from sunlight. As I move forward in programming my Apex to simulate a more natural reef environment, I will incorporate different small temperature variations and see how happy everyone is. This is a fantastic thread, I didn't expect to get so much information. Thanks to all!


S

[sasharotty]

Originally Posted by flyyyguy

Besides, 6 degrees+ isnt an uncommon swing on many wild reefs

x2 Went diving a couple years back and i couldnt believe the temp swings.

[Agu]

My nano tanks vary by three to four degrees on any given day. Over the course of a year they'll vary by about 12 degrees, 72 to 84. Heaters are set to 72 in the winter just in case, but I suspect they could survive even more extreme swings.

After eight years I have yet to see any negative impact from the temp changes.

[greenbean36191]

Here is one summary of a lot of the research out there. I have read a number of the original articles referenced and they seem to be good science. I've also run farily large temp swings myself for many years without issue.
http://www.co2science.org/subject/c/...chresptemp.php

Compared to a lot of what the Idsos have written about adaptability in corals, yes this is a pretty good article in that they get the science mostly right and there are only a handful of facepalm-inducing claims.

However, very little of what's in that article is relevant to hobbyists. Most of the mechanisms that account for the responses they're talking about don't occur in closed systems and those that do, occur only as a result of exposure to stress, which fluctuations (as opposed to spikes) aren't known to induce.

The example they spend the most time on- the Cocos Island recovery (which they neglect to mention was NOT statistically significant) was most likely due to selective mortality leaving behind the most dominant corals and killing off the rest. That's not really something you want to do in a tank. P. lobata, the coral that made up the majority of the coral cover there and which suffered the least mortality, is also probably the most heat-tolerant species of coral. There are documented cases of it living in water in excess of 100 degrees F, which can't be said for very many other species. It's not clear that its ability to survive extreme temperatures tells us much about any other species.

Another main mechanism that gets mention is symbiont shuffling. Basically when corals bleach, they can repopulate their zoox by taking some from the population free-floating in the water. What's often seen is that corals will have one clade prior to bleaching but will take up another, more heat-tolerant clade after recovery. Again, this probably isn't relevant to hobbyists because a) in most locations, these heat-tolerant zoox tend to be fairly uncommon except shortly after bleaching events, so most tanks have few if any corals that would act as sources for them and b) live phytoplankton doesn't last long in a reef tank, so even if you did have a source of clade D, it's unlikely that there are enough live, free-floating cells in the water to inoculate your bleached corals. It's also worth noting that these new symbionts tend not to form stable relationships with the corals. They are usually replaced again by the original clade of zoox unless temperature stress continues. It has also been shown that corals harboring these heat-tolerant clades may be more resistant to bleaching, but less resistant to bacterial disease, so it seems that rather than an adaptive solution to heat-stress, symbiont shuffling is more of an emergency response. This mechanism is also very limited as far as potential for protection from future temp increases. For corals that already have clade C (the most common clade), clade D is the only one that's more heat-tolerant. After you take up clade D (which some corals already have) you're already at the limit of adaptation via symbiont shuffling.

The production of heat shock proteins, which gets a mention, does occur in captivity, but it only occurs following acute temp stress- aka temp spikes. Non-stressful events like temp fluctuations below the mean maximum temp won't induce their production.

[Carpentersreef]

In the December 2010 issue of the magazine Invertebrate Biology, there is an article - Effect of a fluctuating thermal regime on adult and larval reef corals, where the authors study the effects of a daily temperature fluctuation between 21 and 28 degrees celsius (70 - 82 fahrenheit).
They set up a number of 10g tanks where they controlled the temperature using a Neptune controller, heaters and chillers. The temperatures were forced up or down according to the natural temperature fluctuations at Nanwan Bay, Taiwan.
They found that the varying temperature environment made for corals that were stronger and more likely to survive incidences of high heat situations.
I wonder if that isn't the next step in advancing our keeping of corals; trying to even more closely replicate the environment where they originate? How may years ago was it that SPS were deemed impossible to keep?
I think we've got the "survivable" parameters down pat, I would like to see a lot more incidences of coral spawning reported and a lot less reports of "mysterious" coral deaths.
My analogy of how we keep corals now with rock solid steady parameters is like growing a tree in a nice, climate controlled greenhouse. The tree does fine while all parameters are steady and even, but bring along the slightest breeze or other environmental fluctuation and the tree can't take the stress.
Meanwhile, the same species of tree growing outdoors in the wind, rain, heat and cold does just fine.

The article is from my paid subscription, so I don't think I should post it here, but if someone would like me to shoot them a PDF, let me know.

Mitch

[sandgoby]

Mitch,
My thinking exactly!
Thanks
S

[Carpentersreef]

Actually it was the summer edition, not December.

[NirvanaFan]

I pay very little attention to temperature. I stick my hand in my tank when I feed or am doing something with it. As long as it's not real warm or cold, I don't worry. I used to monitor it and would see 5 or 6 degree swings daily. No problems were ever saw.

[akindbro4u]

I don't worry about the daily swings, just the highs, and the lows. Gotta play the over under.

[Cozmo4]

So if the thought it that a temp fluctuation is good for coral resilience, would anyone suggest forcing a temp swing if it doesn't naturally occur? I'm running LEDs on my 210g with Vortechs. I've got very little heat being generated. My other tank swings about 4 degrees naturally from heat from the lighting. Should I set my controllers to gradually increase temp through the day and allow it to fall at night?

[tmz]

Originally Posted by greenbean36191

Compared to a lot of what the Idsos have written about adaptability in corals, yes this is a pretty good article in that they get the science mostly right and there are only a handful of facepalm-inducing claims.

However, very little of what's in that article is relevant to hobbyists. Most of the mechanisms that account for the responses they're talking about don't occur in closed systems and those that do, occur only as a result of exposure to stress, which fluctuations (as opposed to spikes) aren't known to induce.

The example they spend the most time on- the Cocos Island recovery (which they neglect to mention was NOT statistically significant) was most likely due to selective mortality leaving behind the most dominant corals and killing off the rest. That's not really something you want to do in a tank. P. lobata, the coral that made up the majority of the coral cover there and which suffered the least mortality, is also probably the most heat-tolerant species of coral. There are documented cases of it living in water in excess of 100 degrees F, which can't be said for very many other species. It's not clear that its ability to survive extreme temperatures tells us much about any other species.

Another main mechanism that gets mention is symbiont shuffling. Basically when corals bleach, they can repopulate their zoox by taking some from the population free-floating in the water. What's often seen is that corals will have one clade prior to bleaching but will take up another, more heat-tolerant clade after recovery. Again, this probably isn't relevant to hobbyists because a) in most locations, these heat-tolerant zoox tend to be fairly uncommon except shortly after bleaching events, so most tanks have few if any corals that would act as sources for them and b) live phytoplankton doesn't last long in a reef tank, so even if you did have a source of clade D, it's unlikely that there are enough live, free-floating cells in the water to inoculate your bleached corals. It's also worth noting that these new symbionts tend not to form stable relationships with the corals. They are usually replaced again by the original clade of zoox unless temperature stress continues. It has also been shown that corals harboring these heat-tolerant clades may be more resistant to bleaching, but less resistant to bacterial disease, so it seems that rather than an adaptive solution to heat-stress, symbiont shuffling is more of an emergency response. This mechanism is also very limited as far as potential for protection from future temp increases. For corals that already have clade C (the most common clade), clade D is the only one that's more heat-tolerant. After you take up clade D (which some corals already have) you're already at the limit of adaptation via symbiont shuffling.

The production of heat shock proteins, which gets a mention, does occur in captivity, but it only occurs following acute temp stress- aka temp spikes. Non-stressful events like temp fluctuations below the mean maximum temp won't induce their production.

Very informative posts. Thanks

[therealshark]

good info, i was worried about this awhile back when my tank would swing 4 to 5 degrees and have since made it abit better. now only about 2.5 degree swing daily. i guess i really didnt have to worry about it.

[greenbean36191]

So if the thought it that a temp fluctuation is good for coral resilience, would anyone suggest forcing a temp swing if it doesn't naturally occur? I'm running LEDs on my 210g with Vortechs. I've got very little heat being generated. My other tank swings about 4 degrees naturally from heat from the lighting. Should I set my controllers to gradually increase temp through the day and allow it to fall at night?

There's no need to force a larger swing than what already occurs. Generally, my advice is to let the temp swing as much as it wants to on its own as long as you keep the high temp consistent. If it goes from 76-84 during the day, that's ok, but so is a tank that stays 83 all day long without a chiller or heater since none of the common modes of failure (power goes out or heater or chiller dies/sticks on) is going to give you a stress-inducing spike.

The main concern is that people don't use their heaters and chillers to try to keep their tank +/-0.5 degrees, creating a situation where if their equipment fails or the power goes out, they're going to get a temp spike/drop of several degrees as the tank settles on its natural temp.