reef temp confusion (moderators & successful reef)

[mysterybox]

Dear moderators & successful SPS keepers:

I realize that most tanks are in the 78-82 range, so I'm not sure if a 2 degree swing from 80 really matters as long as all things are stable, but lately, I have been bombarted with experienced keepers stating 76-78 is the way to go (Including Sprung & Delbeek's The Reef Aquarium Volume 3)

On the other hand, Eric B. IS THE CORAL BREEDING GURU! He breeds them from spawning in captivity & has been very successful for many, many years. What do you think?

Here's my post to Eric:



Dear Eric,

I really liked your interview & Q&A on 120! It was very enlightening, and it was great to hear what your passion was. Also, I have a question on temp. For the last 2 years, i have kept my temp at 80 degrees 24/7. This has been very easy. While my lights are on, my sump fan keeps it at 80F, & at night, my heater keeps the temp at 80. I was thinking it might be better to let it swing to 78 degrees at night. I was told that stonies do better at a slightly lower temp, & the 2 point swing would closely mimic nature. I would keep the temp at 80F during the day. What do you think?


Ralph



Eric Borneman


There are relatively few tropical coral reefs that are in the 70's except perhaps slightly more subtropical ones during winter or those that happen to exist in areas of persistent upwelling or colder currents. Few of the animals, especially corals, are collected from these areas. Temperatures on the reefs where are animals are collected are generally always above 80 and generally below 88. Daily swings of from 0-12 degrees F are not uncommon and can happen several times a day. Temperature is truly not one of the things to worry about in tanks unless you can say what strains of zooxanthellae are present, where the corals were collected from, what species (and thus their environmental sensitivity), synergistic stressors (as corals do well near their upper thermal limits) and to ensure that temperatures do not exceed, say, 90F for extended periods of time. A swing from mid70's to 90 (for example, a heater malfunction) that lasts for a day will probably cause problems for some animals if they are acclimated to a constant temperature. The problems with losing animals from temperature related events is what happens when they die in a closed system and most of the mass tank losses from such events is probably not a direct result of high temps alone. But, I also feel that given the multitiude of things that can go wrong in tanks and the fact that they are tanks withouth the inherent variability of the ocean, that pushing temps to the uppper limit where they might be happiest in the wild may not be ideal in tanks. So, I think 82-84 is right where you have some safety margin in upper thermal limits and within the range where most tropical reef corals and those collected for the trade do best.

[Billybeau1]

The first point I will agree with, and have always believed, is you cannot compare the ocean to our reef tanks. Apples and Oranges.

Certainly, if there is a dieoff due to some problem, it affects the chemistry of a reef tank much harder than the ocean.

Fish can move from warmer to colder and colder to warmer. Corals can't.

Although this is a better question for the SPS forum, I think every tank is different and has different inhabitants with different needs.

You need to strike a happy medium in YOUR tank to ensure success.

Only your eyes will tell you that.

[mysterybox]

Great answer! Thanks!

[bertoni]

I target 82 F as the base temperature for my tanks. I haven't seen any reason to go lower for a tropical reef tank. I agree with Eric's analysis. There's a lot of studies in this area, if you want to do some research.

[dots]

I remember seeing a chart, from him possibly, corelating growth rates with temperature. It showed the growth was faster during the summer months and slowed when cooler. Which is how it tends to work anyways in nature, so its not that much of a stretch to belive.

However, as I have found out the hard way lately, what you see ain't always what you get in your data. I plugged in a new Won controller for my Jali heater this week. My therometer read 80, my chiller display read 82 and the controller, which I "hope" is the most accurate read 84.

Time for the lab grade thermometer or an ice bath, hopefully the probe will go down that low.

Any other suggestion for a standard that could be available around the house that will be within range?

My point is, I agree 100% 82 would be great and would save on electricity of a chiller running and have better growth and thought I was set there. But honestly, with all the precision and accuracy of instruments all over the place as shown here with my example, perhaps 80, is a more conservative number for the average reefer so as not risk pushing the upper limit and causing a melt down? I learned pushing the alk limit the hard way and had a nasty alk creep during my last semester of college. I try to keep it in the middle for some wiggle room if needed now. My priority is to keep the suckers alive first and growing fast second.

Besides, with temp variations as stated, whats two degrees in the grand scheme of things........maybe its early Saturday morning and I am just splitting hairs?

[mysterybox]

I'm going to 82F. Thanks for all of your input.

[bertoni]

The accuracy of measurement issue is important. I bought a thermometer from Cole-Parmer that was calibrated and had a specified accuracy.

[mysterybox]

I use a thermocoupler to verify my therm now & then.