damsels are not mean
Valuable Member
I was researching coral shipping and temperatures and so on and came across this older thread: https://www.reef2reef.com/threads/heat-pack-study.96954/
It seems to be the only one I've seen with data on temperatures over several hours in the cold simulating shipping. I would love to see any and all data on this that you are aware of. Maybe I will conduct my own tests as well, but I don't have a temperature logger.
The conclusion I've drawn from the (admittedly limited) data and also the posts by others, is that typical heat packs are at best useless and at worst harmful during shipping for corals. In summary, the heat packs can't get enough oxygen after the initial supply is exhausted, so they don't actually have any effect after the first hour or so. The difference in temperature at the end of the tests results from a spike at the beginning for the tests with heat packs (which is more likely to kill your corals than slowly declining temps during overnight shipping) and multiple heat packs don't make any difference at all compared to single ones. If you were going to use a heat pack, it seems you are better off just running your frag tank hotter. After the initial spike, the temperature curve is indistinguishable between heat pack and no heat pack. Another poster claims to have run similar tests even with ventilation holes to keep the heat packs running, and found that this made little to no difference. This post doesn't come with data, but the assertions are backed by equations too.
I haven't seen any other studies or data on the topic, and although it seems intuitive that we need some way to keep our corals warm in transit, I am not sure this is the case. I have received plenty of cold (like 40s and 50s) coral packages and never lost any. Often customers find an apparently "still warm" heat pack and assume this means the coral was packed well. In reality, the heat pack likely started to heat up when they opened the package. There are plenty of anecdotes, and heat packs are an industry standard. But like many other things in hobby-based industries, industry standard methods can result from somebody smart saying something intuitive and then everyone doing that because it makes sense. The idea that heat packs keep the package warm is a comforting thought because it gives us a sense of control.
Now, we know corals will do better under warmer temperatures (although again I believe they are more resilient to short term cold than most assume), and it seems our conventional heating solutions are pretty ineffective. Are there alternatives? What about tiny electronic heating units? There are also gel-based handwarmers that are reusable. Is there any good way to store heat? I know water volume is good for this, but perhaps there are even better materials.
It's possible we don't really need heatpacks at all, and that focusing on well-sealed insulation is far more important than any sort of heat generation. What are your thoughts? Have you done any testing?
It seems to be the only one I've seen with data on temperatures over several hours in the cold simulating shipping. I would love to see any and all data on this that you are aware of. Maybe I will conduct my own tests as well, but I don't have a temperature logger.
The conclusion I've drawn from the (admittedly limited) data and also the posts by others, is that typical heat packs are at best useless and at worst harmful during shipping for corals. In summary, the heat packs can't get enough oxygen after the initial supply is exhausted, so they don't actually have any effect after the first hour or so. The difference in temperature at the end of the tests results from a spike at the beginning for the tests with heat packs (which is more likely to kill your corals than slowly declining temps during overnight shipping) and multiple heat packs don't make any difference at all compared to single ones. If you were going to use a heat pack, it seems you are better off just running your frag tank hotter. After the initial spike, the temperature curve is indistinguishable between heat pack and no heat pack. Another poster claims to have run similar tests even with ventilation holes to keep the heat packs running, and found that this made little to no difference. This post doesn't come with data, but the assertions are backed by equations too.
I haven't seen any other studies or data on the topic, and although it seems intuitive that we need some way to keep our corals warm in transit, I am not sure this is the case. I have received plenty of cold (like 40s and 50s) coral packages and never lost any. Often customers find an apparently "still warm" heat pack and assume this means the coral was packed well. In reality, the heat pack likely started to heat up when they opened the package. There are plenty of anecdotes, and heat packs are an industry standard. But like many other things in hobby-based industries, industry standard methods can result from somebody smart saying something intuitive and then everyone doing that because it makes sense. The idea that heat packs keep the package warm is a comforting thought because it gives us a sense of control.
Now, we know corals will do better under warmer temperatures (although again I believe they are more resilient to short term cold than most assume), and it seems our conventional heating solutions are pretty ineffective. Are there alternatives? What about tiny electronic heating units? There are also gel-based handwarmers that are reusable. Is there any good way to store heat? I know water volume is good for this, but perhaps there are even better materials.
It's possible we don't really need heatpacks at all, and that focusing on well-sealed insulation is far more important than any sort of heat generation. What are your thoughts? Have you done any testing?
This has to be a troll lol
