20 degree temperature swing and no dead corals?? :O

[Anonymous]

I'm curious if this is a "count myself lucky" situation or what. I recently set up a 30g prop tank near a south facing window, and I'm testing it with various zoos, candy cane, a colt coral, gsp, mushrooms and one orange dig frag. So far the corals look great due to the natural sunlight (might be overpowering the mushrooms, but I expected that) well yesterday I don't know what caused it (but may make me remove the tank if it keeps up) the temp rised to about 88-90 degrees in the tank, so I put a fan to blow across the top and opened a window to try to cool it off, well I went to a superbowl party shortly after, when I came home later the temperature was 68 degrees! So I had a temp swing of 20 degrees, now my colt was looking peed off and my candy cane were super puffed up, but this morning with a the temp stablized they all look normal. So I'm wondering if I just got really lucky here or what. Everyother time I've heard swings like this due to hotweather (and lack of chiller or A/C) people have had much worst results. So what could have allowed mine to survive? Just hardier species? or what?

 

[Anonymous]

Ummm, I bet that you may not have seen all the effects as of yet. Still you might not have as many problems as you think. Good Luck!

 

[wade1]

Colder is always better than warmer! I have seen acro's kept at 60F for 6 hours and then brought back up slowly and not bleached a bit. I'm betting the metabolism slows way down, but doesn't cause any direct problems like increases in temperature do.

I would still keep an eye on things, but you might be ok if you can keep it stable now.

 

[Anonymous]

Ahh, well the only thing in the tank is baserock, so its not like there's a whole underlying ecosystem in there (atleast I dont think so) that could have potentially died off, so maybe that's why it didn't suffer too much damage. But I'll keep an eye on things, everything looks fine today though.

 

[Anonymous]

Seems to me that most reefs especially shallow reefs would experience that temperature change in that time once every 20 years or so. So I think a one time dip over hours should not cause any lasting problems.

 

[wade1]

Are you suggesting that a natural tropical reef would see a 20oF temperature drop ever?!?!? If so, you are wrong. There are plenty of sites on the internet that track sea temps in tropical locations.. they might go up and down 10 degrees, but not 20.

 

[Anonymous]

Are you suggesting that a natural tropical reef would see a 20oF temperature drop ever?!?!? If so, you are wrong. There are plenty of sites on the internet that track sea temps in tropical locations.. they might go up and down 10 degrees, but not 20.

my first post was intuitive but I did find this thread:

http://www.reefs.org/library/article/re ... ature.html

in which Ron Shimek states:

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

So iI guess I was not all that far off.

 

[Anonymous]

Hmm that's interesting. Fish are cold blooded and I'd think that type of swing would really be harmful. I even saw a special that says that temperatures of a couple degrees due to global warming can kill the reef, maybe if its a long term temperature change? (ie they can only stay slimed up/dormant for so long). But hey I'm not going to argue if my corals didn't get damaged

 

[wade1]

Ok, I went a little overboard, true. However, those atolls and reefs that see the largest temperature fluxes usually see them due entirely to enclosed systems (ie- sunlight heats a body of shallow water during the day and it is not flushed well). There most certainly are corals that will survive those fluxes, and even massive salinity fluxes (ie- the red sea in areas that hit 1.040+), but not many. The diversity in those areas are extremely limited.

Fish can certainly withstand changes more readily than corals.

The jist of what I was trying to get across is that for your average home hobby tank, the diversity of corals cannot withstand that sort of flux. Sorry for jumping on it like that without more explanation...

Wade

 

[Anonymous]

First of all I am glad the corals are ok.

And Wade I do understand.

FWIW it seems to me that an aweful lot of what we try to do is to mantain constant and optimum conditions. And those condition(s) may and probably do result is the absolute fastest say-- grow rates possible. So we wind up spending tons of money on specialized equipment each of which has a new possibilities of failure and requires new maintenance procedures. but slightly off optimum conditions which do vary but are stable would probably work just as well or at the most say result in growth rates that are 80-90% of the optimum. And require not only less money but less maintenance with less possibility of failure.

In this particular thread my "gut feel" was based upon 1.5 years of reef operation plus 25 years of FO and FW operation at various locations with no heaters. Temperature varies 3-5 degrees per day and everything does fine. Not only have I not had tank crash when I have established the plant growth, but I also have never had a tank crash because of a heater malfunction for instance.

JMHO. I think your reef will be fine.

 

[dougc]

I have seen low temperatures do bad things to montipora species. Acros, softies, and LPS seemed to be less affected. I do agree that high temp is worse than low. Before having a chiller, my temperature would sometimes hit 86-87 in the summer, and I had some acros that would have bouts of recession at those temperatures. Those species probably just wouldn't survive in an area with great temperature swings.