79 - 79

The more constant the temp the better off you are.

79 - 79

The more constant the temp the better off you are.

any reasons as to why??  Why 79 and why should it stay constant??

Stress is the main reason why you want to keep it as level as possible.  I keep mine at 79, the reason is that that is were it likes to migrate to.

Once my lights come on I have a hard time keeping it cooler then 79.  SO I try to maintain 79 rather then have the temp spike.

"No matter what temperature you decide to maintain your system at, the general consensus here is that any marine animal exposed to quick changing water temperatures will be stressed, and even though they may be able to handle the change for only a ever short time, if continually exposed they will probably die. When it comes to tank temperatures that are changed rapidly, or that may be constantly changing in degrees too much up or down for short periods of time, a variation of even 2� F can be enough to cause problems, especially for corals and other invertebrates. However, with gradual acclimation, marine organisms are amazing creatures and can adjust to their environments. To avoid the common pitfalls of temperature problems, the most important thing is to maintain a STEADY temperature at all times! "  ( http://saltaquarium.about.com/cs/waterquality/a/aa061002_2.htm - http://saltaquarium.about.com/cs/waterquality/a/aa061002_2.h tm  August 30, 2004)

Excellent point Jake.  What advantage does the cooler temps provide?? 

Great info Kull!!  I agree BTW.  Consistence in everything is very important IMO.

Here are some "Expert" opinions:

"

• http://clk.about.com/?zi=1/XJ&sdn=saltaquarium&zu=http%3A%2F%2Fwww.animalnetwork.com%2Ffish2%2Faqfm%2F1997%2Fnov%2Ffeatures%2F1%2Fdefault.asp - Ronald Shimek's view is that corals you have in your tank may come from many different ocean water temperatures, ranging from 72� F up to about 92� F. For example, keeping reef organisms from the central Indo-Pacific in the upper 70� F range will stress them, as it is too cold, because this is near the upper limits for subtropical organisms. He states that, "It would be better for all concerned if aquarists concentrated their efforts on maintaining separate systems for organisms from geographically disparate areas." In other words, knowing what kind of organisms you have and "where" they come from is an important factor when determining a tank temperature for your system.

• http://clk.about.com/?zi=1/XJ&sdn=saltaquarium&zu=http%3A%2F%2Fwww.animalnetwork.com%2Ffish2%2Faqfm%2F1998%2Fmar%2Ffeatures%2F1%2Fdefault.asp - Richard Harker's view is that, "A hobbyist who decides to increase the temperature of his or her tank needs to make sure that it is a stable tank with healthy corals, no sign of algae, and has equipment necessary to efficiently remove the increased waste products. Under these conditions it would be safe to increase the tank's temperature." However, he points out that rather than trying to run your temperatures high, you should reach a happy medium at about 79 degrees, because this temperature provides the largest margin of safety for the hobbyist, as corals have been shown to thrive in water several degrees on either side of this temperature"

( http://saltaquarium.about.com/cs/waterquality/a/aa061002.htm - http://saltaquarium.about.com/cs/waterquality/a/aa061002.htm  August 30, 2004)

Again for me it isn't really what temp you choose to keep the system at it is maintaining it.

Also where the temp changes so does your ph and amount disolved Oxygen in the water also other import factors in keeping a healthy reef are affected such as the rate of decay, how quickly algae grows ect.

Kull wrote: Once my lights come on I have a hard time keeping it cooler then 79.  SO I try to maintain 79 rather then have the temp spike.

This is one major reason I keep mine at 80.  It gets a little hotter during the summer but usually stays around 80.  Peaks at 82 on hot days.

What does everyone consider the perfect temp range?? 

76�F days - 68�F nights... San Diego would be my paradise if it weren't for all those people!

If I could, I would keep my tank at 78�F, but I can't during the summer so for the last few months I've kept my tank at 80�F.  Come fall/winter, I'll drop it back down to 78�F (or maybe not??).  I also try to keep it as constant as possible.

More good info kull!!

 that would be nice Jon... 

A little incite as to the purpose of this post...  I took my heaters out for a water change over the weekend and forgot to put them back in.  Wake up Sunday and the tank that is usually at 80 was at 74.  IMO that's 'way' to much of a swing... so it got me thinking.  edit: btw, this is not another heater vs no heaters thread...  not conserned about heater, just what the best temps are.

I've read articles that recommend 74-78, others that recommend 78-82 and some recent one that recommend 82-86.  & no real reasons as to why. 

The above articles are about the best as they recommend matching the critters with their natural environment or coming up with an average to accommodate them both.

As with most disolved gases, the higher the temp the lower the concentration of disolved gases.  Where is the chemist?  I was sure he would have something to say, I'm no chemist, but I do remember a few thngs from the days that I played one at School.

Some suggest that you can offset the to some extent the cause the higher tempuratures have on the disolved hases present by incresing your water flow.  I think that this is true to an extent, Water flow will make is so that you have available gasses thoughout the tank, and the concentration will be equal, it will keep you form having "dead zones" 

At any rate this is my 0.50

Good luck.

I like lower temps for 2 reasons.

1.  Increased available O2.

2.  Lesser chance of "crashing a tank".

The only problems are:

1.  Corals and fish grow slower in cooler waters (not much though).

2.  It is hard (sometime impossible) to keep your temperature down.

If you want to see how temperature and salinity effect O2 saturation check out this calculator:  http://www.aquanic.org/images/tools/oxygen.htm - http://www.aquanic.org/images/tools/oxygen.htm

Increasing your water flow can help you reach the saturation point, but can't boost you over it.  FWIW, I personally think that within the temperature ranges we are concerned with, it doesn't matter. 

From that program (O2 saturation):

76F/35 ppt/4300 ft elevation = 5.843 mg/l
82F/35 ppt/4300 ft elevation = 5.513 mg/l

That's only a 5% drop in oxygen.  Is that significant?

More interesting to me is the difference due to elevation ... 

Jake, are the tank crashes you are referring to due to over heating??  The largest problem for me so far is preventing temp drops.  This is not the first time the tank has hit the low 70's... 

Increased temperature is said to increase the inhabitants' metabolism.  I notice an increase in activity when the tank gets above 80.  Sunday everything seemed pretty lazy. 

Does anyone run on the high side (82-86)??

Some interesting information from Aquarium Corals, Selection, Husbandry, and Natural History by Eric H. Borneman.

In a study of 1,000 natural reefs the average temperature was found to be 82deg. Of those reefs tested the lower temperature reefs averaged 77deg and the higher temperature reefs averaged 86deg.

Travis wrote: More interesting to me is the difference due to elevation ...

No wonder I can't run here.

I think my tank is around 82. I'll have to check tonight

Travis wrote: Jake, are the tank crashes you are referring to due to over heating??

No.  Almost every tank I have seen crash is due to some large organism quickly wasting away in a tank (usually a coral).  The lower the temp the slower the organism will pollute the tank giving you more time to remove the organism avoiding a crash.  Also one of the biggest reasons that the whole tank crashes is due to lack of O2.  When a coral starts to waste away most of the available o2 in the water is used in decomposing the dying tissue.  The lower the temp the slower the decomposition.  The slower the decomposition the better chance of having more o2 to keep the rest of the organism alive.

jfinch wrote: 76F/35 ppt/4300 ft elevation = 5.843 mg/l 82F/35 ppt/4300 ft elevation = 5.513 mg/l That's only a 5% drop in oxygen.  Is that significant?

Jon, that answer is so you (an engineer response), but I don't believe a simple formula can calculate the effects of the temperature difference.

Keep in mind:

-The higher the higher the temperature the faster organisms use up available oxygen (their metabolic rate increases).
-The faster the metabolism of the organisms in your aquarium the more waste they put out.
-The more waste they put out the more oxygen is used in filtering that waste

So you have more then just the 5% decrease working against you.

So you have more then just the 5% decrease working against you.

That's a good point but the calculation simply shows the point of saturation... not the available O2 in the system.  I would find it hard to believe that any of us come close to saturation (anyone have a O2 test kit??).  All this really tells me is more effort needs to be made to assure good gas exchange in a higher temp system.

Jon, that answer is so you

 At least I'm predicable

Jake, I agree with everything you said in the above post.

I guess I was coming at this from a different perspective.  I've heard many people say they prefer lower temperatures because O2 is more soluble at lower temperatures (it was implied in this thread).  That's true, but not significant, imo.  That calculation only tells how much oxygen will saturate the water.  If I were to take a beaker() of seawater and bubble air through it, it would become saturated in oxygen and there would be about 6 ppm O2 (at either 76 or 82F).  This doesn't mean that your tank will be necessarily at that level.  Life gets in the way of that as you've pointed out.

I would find it hard to believe that any of us come close to saturation

You can buy dissolved oxygen probes to measure this.  I've seen very mixed reports from people who have them.  Some report vastly undersaturated conditions while others report supersaturated levels during the day and lower at night.  I see no reason why a well stocked (corals/algae) tank couldn't supersaturate in O2 during peak photosynthysis.  Rapidly growing freshwater planted tanks bubble O2 regularly.

Travis- I checked my tank and I'm running 82-84.

Suzy- I think it would be beneficial to have the fry at a higher temp. Could a higher temp allow the fry to mature faster, thus increasing their survivability?

Others-If oxygen levels drop with a higher temp, do CO2 levels rise? or are they not related?

Is another benifit of running a refugium on reverse daylight be more stable oxygen levels? (sorry if this questions seems dumb)

I agree with Jake.

Adam

Suzy wrote: So, not to change the subject, but if a person was unsuccessfully trying to raise baby seahorses, and the water was a little chilly, around 74`, would that slow their metabolism, thus slowing their growth? Would that be a good thing because it would also keep the water chemistry better? Could I compensate with higher temp and more water changes?

Yes, yes.  Yes and No.  Maybe.

Well if our systems can actually reach saturation or even supersaturation then the difference in O2 levels due to heat is a mute point... because obviously there would be plenty O2 for the critters.

Is another benifit of running a refugium on reverse daylight be more stable oxygen levels?

Yes, it should.

jfinch wrote: 76F/35 ppt/4300 ft elevation = 5.843 mg/l 82F/35 ppt/4300 ft elevation = 5.513 mg/l That's only a 5% drop in oxygen.  Is that significant?

Jon,
yes and no.  At 86F saturation is 4.5 mL/L and at 70F it is 6.4 mL/L.  That seems like a jump.  I do agree we are at saturation.  But as Jake mentioned the real key is metabolism.  Also very important...

Hemoglobin can be similarly affected by changes in temperature, with affinity for oxygen decreasing as temperature increases.  This is one reason that typically cold water fishes often cannot survive at higher temperatures, even if the oxygen content of the water is increased.  At these higher temperatures, the structure of the fish's hemoglobin may be altered to the point where the fish simply cannot pick up enough oxygen at its gills and therefore could suffocate even though sufficient oxygen was present in the water - (Helfman et al, 1997).

Adam 

Wow... just getting around to replying to this thread Adam? 

At 86F saturation is 4.5 mL/L and at 70F it is 6.4 mL/L.

Where did you get those numbers?  Are you sure on the units?  I was reporting in mg/l.  In ml/l your 86F number looks ok, but the 6.4 ml/l at 70F looks suspicious.  I think it's closer to 5.1 ml/l...

BTW, I agree with the metabolism issue. 

Yeah I took the numbers straight out of the research.  I was also questioning your units, as mine are in ml/L not mg/L.  These are at sealevel, actually in the sea I should say. 

Sorry for the delay on replying, been reading on this for a while now and just like you.... sitting at work today....

Adam

You have research numbers in ml/l?  I would think that the original/tested values in that research were in either mg/l or umol/l (I don't think you can get ml/l directly from a test)?  

But values given in volume (i.e. ml/l) can be converted to mass or molar units by using the appropriate equation of state (I used the ideal gas law to convert your numbers, cause I'm lazy) if you know the pressure and temperature.

At sea level and at the temperatures you posted those values convert to:

4.5 ml/l (@86F) = 5.82 mg/l = 182 umol/l
6.4 ml/l (@70F) = 8.57 mg/l = 266 umol/l

The 8.57 mg/l is too high I think.  Here's a couple references:

http://www.aquanic.org/images/tools/oxygen.htm - http://www.aquanic.org/images/tools/oxygen.htm  this will calculate O2 saturation at any salinity, temperature and elevation.  This reference gives 7.25 mg/l.

Chemical Oceanography, Frank J. Millero, p. 247 - 259 covers dissolved O2 in seawater.  Table 5.10 shows dissolved O2 vs. temp for saturation conditions.  It shows 185 umol/l (5.92 mg/l) at 86F and 220 umol/l (7.04 mg/l) at 70F.

http://www.reefs.org/library/article/r_toonen14.html - http://www.reefs.org/library/article/r_toonen14.html  is an article by Ron Toonen regarding this very topic.  Interpolating his data results in an O2 level of 7.5 mg/l.  And he even feels the same way as I do regarding the amount of O2 dissolved.  Here's a quote:

While it is true that both salinity and temperature will affect the particular value of the oxygen saturation coefficient in seawater (e.g., if you're being good and maintaining your tank at a natural salinity of ~35 ppt -1.026 SG-, then the oxygen saturation at 25C is 6.9mg/l, while at 30C is only 6.4mg/l), this is pretty much a non-factor. If the difference of 0.5 mg/l of oxygen in your tank makes any difference to the inhabitants of your tank, you are *seriously* under-circulating or overloading your tank!

Jon-
I agree that it is a small amount in the 5 degree F range.  But over 20 degrees it is worth mentioning. 
But still, not nearly anywhere near as important as the metabolic and hemoglobin factors.

Adam

Suzy- I agree. That is a big difference as well.  In fact most fish use that (which I call the Bohr effect) to their advantage for respiration.  That may be more important than all the items we're listing here.

Adam

Mark-
Higher pH has a higher affinity for oxygen.  (For hemoglobin that is)
The big problem with high pH (in my opinion) is that it is like very low pH.  The high basic solution "burns the gills" of the fish and causes respriratory problems. 

Adam