Any reason we keep our tank temps so low?

[MoreReefPlease]

So, I've been battling diatoms dusting my rocks and sand in the morning when lights comes on and I came across a thread where raising temps to 82° F, helped get rid of them.
I usually keep my temps at 78-79° F with this larger tank, which as all of us know is the generally recommended temperature to run a reef at.

With my previous tank - a 29g JBJ - I ran a 150w MH, 3 inches off the water. My temps were high enough that I needed a fan on the top tank blowing across the water to lower it to 80-81° F.
That tank FLOURISHED. I had so much biodiversity, coralline and coral growth that within a year my tank had doubled the size of the frags and produced so many BTA's for me to sell that I almost recoup all the money I spent getting it up and running it.

Fast foward three years later, after a move across the state, my tank crashed and I lost 85% of what was in it. My new tank has been up almost a year but the growth has been SLOOOOOW, and this is with more money, better equipment and a larger more stable environment.

I can watch the same speck of coralline on a pump not grow for weeks on end.

TLDR; The average temperature of ocean water in Raja Anpat is 84°, historically. This is the most biodiverse reef on the planet.
The average temperature of ocean water in the Solomon Islands, the second most biodiverse reef system in the world, is 84°.
The average temperature of ocean water in Anguilla, one of the largest reefs in the Caribbean, is 82° F.

Why do we keep lower temperatures than the reefs we're trying to imitate? I'm increasing my slowly to 82° to see what the results are on growth.

 

[tehmadreefer]

My nicest tanks in the past ran high temps 82-85 and higher nutrients I don’t believe there is an actual reason to keep the lower temps as that is just considered the standard for whatever reasons.

run it how YOU want, it’s YOUR tank.

 

[piranhaman00]

Keep it consistent and stable and within 74-85 F and you will be fine

 

[Nano sapiens]

A few rationale behind lower temps:

1. Lower temperatures have more oxygen in the water than higher (important for a heavily stocked reef aquarium and/or one with a DSB, especially when the power goes out)
2. If a heater malfunctions and gets stuck 'on', there is more time and therefore a greater potential to catch the rise before it becomes critical.
3. Reef fish tend to live longer due to the lowered metabolism
4. Reef fish parasites' metabolism is slowed, so less reproduction/infestation

I've run different reef tanks from 76-78 all the way up to 82-84 F. The way a system is set up, the bioload, aquarist's risk tolerance and desired rate of growth all play a part in the decision to run at a specific temperature.

 

[h2so4hurts]

Stability below about 85 is key. Don't chase 78, there's really no reason to.

 

[Randy Holmes-Farley Verified Community Expert]

A few rationale behind lower temps:

1. Lower temperatures have more oxygen in the water than higher (important for a heavily stocked reef aquarium and/or one with a DSB, especially when the power goes out)
2. If a heater malfunctions and gets stuck 'on', there is more time and therefore a greater potential to catch the rise before it becomes critical.
3. Reef fish tend to live longer due to the lowered metabolism
4. Reef fish parasites' metabolism is slowed, so less reproduction/infestation

I've run different reef tanks from 76-78 all the way up to 82-84 F. The way a system is set up, the bioload, aquarist's risk tolerance and desired rate of growth all play a part in the decision to run at a specific temperature.

I would add to that list is what happens in a power failure.

I ran my tank temp a bit higher in winter and lower in summer to buffer against power loss and temp changes.

 

[92Miata]

Because long term heat stress is worse than cold stress. And yeah - runaway heaters are a thing.

"These results suggest that short-term cold temperature is more damaging for branching corals than short-term warm temperature, whereas long-term elevated temperature is more harmful than long-term depressed temperature. "

Cold induces acute stress but heat is ultimately more deleterious for the reef-building coral Acropora yongei - Scientific Reports

Climate change driven increases in intensity and frequency of both hot and cold extreme events contribute to coral reef decline by causing widespread coral bleaching and mortality. Here, we show that hot and cold temperature changes cause distinct physiological responses on different time scales...

www.nature.com

 

[Nano sapiens]

I would add to that list is what happens in a power failure.

Mentioned under # 1.

 

[Randy Holmes-Farley Verified Community Expert]

Mentioned under # 1.

Yes, but I meant the higher in summer, lower in winter part.

 

[Nano sapiens]

Yes, but I meant the higher in summer, lower in winter part.

Ahh, I see...got it

 

[h2so4hurts]

Cold in that study being 70 and hot being 88. Seriously, just keep it below 85. I have my heater set to 76. Tank is 78 in the winter 80-81 in the summer. No ill effects whatsoever. Heater is just there in case something bad happens in the winter. If power goes out in the summer, well, I guess it's a good thing the tank is in the basement. It'd take days to heat a 500 gallon tank out of the safe range. Maybe I should get a chiller to hook up to the generator just in case

 

[tehmadreefer]

Well the whole fish live longer doesn’t apply to 99% of ppl since they get out wayyy longer than their fish dying of old age for certain.

I don’t run a heater

 

[Montiman]

Another reason is we are seeing more and more deep water species in the hobby. It is my experience that shallow water fish better adapt to 76 than deep water fish adapt to 82.

 

[MoreReefPlease]

My heater is always on, connected to an additional control box and I live near Chicago so my chances of anything overheating are very low. The -50 year before last was definitely not fun for this Florida boy.

I'm going to slowly increase my temp over the next 2-3 weeks to 81° F and see what happens. Might go up to 82°.