Raise temperature to 79?

[aaron186]

I’m currently running my tank at the standard 78 deg F. I’m using a wifi controller with an apex for backup. I live in Florida and my tank is in living room where I have a large slider opening to my pool so the doors are left open kinda often. I’ve noticed over the summer that my tank is often creeping up to 79-80 on occasion. It’s never gone above 80. I don’t have room for a chiller and my sump is crowded making a fan a bit tricky as well.

I’m wondering if I should just set my temp range a little bit higher to avoid swings. My controller has a 0.5 range on it. So I was thinking 78.7-79.2. Is this a good idea? (Current setting is 77.7-78.2)

 

[ISpeakForTheSeas]

Your tank should be able to handle a 2-3F swing daily, but raising the temp a little shouldn’t hurt either (from what I’ve read, ~83F is a relatively safe maximum temp, and ~75F a relatively safe minimum temp).

Slightly diurnally and seasonally, yes:
"The diurnal temperature variations are about 0.3°C in theopen oceans and 2 to 3°C in shallow waters."
Source: https://www.academia.edu/36838790/Chemical_Oceanography
From what I've seen, for most tropical reef organisms, as long as the temp doesn't swing too far too fast, and as long as the temp is kept within ~75-82F (lower than 74ish can start causing problems, higher than 83 and many corals will start to bleach - so allowing for temp variation due to imperfect temp controllers in our tanks, I would set 75F as the min and 82F as the max), the temp doesn't seem to matter much. To give an idea, a 2C change (from 25C to 27C, for example) is about a 3.5F change (77 to 80.6, with the 25C to 27C example), so allowing a 3F to 4F temp change diurnally should be fine.

I’ve been reading through a bit of literature on corals and temperatures, and - generally speaking - 83F is considered the safe limit you don’t want to go beyond, so some people might recommend not going above 82 as a precaution.
Edit: when accounting for the slight inaccuracies of our heaters/controllers, I personally would set 82F as the limit.

That said, though, there are a number of caveats that determine what temperature is too high. To list a few:
1) the location the coral was collected from (some coral reefs have higher temperature tolerances based on their geography than others - 83F [technically like 83.6F or so] is the limit for the least heat resistant reefs, if I recall correctly; I believe somewhere around 87-89F was the limit for the most heat resistant).
2 ) temperature stability (the more stable the temperature the coral is used to, the less it’ll like changes to temperature).
3) how long the coral has to acclimate to the higher temperature (slow and steady wins the race).
4) corals can handle temperatures above their temperature limit for a limited amount of time (if the temperature is only slightly over, the corals only start showing distress/begin bleaching after a few days [four days at 1-2F over, if I recall correctly]; if the temperature is significantly above the limit, the corals will show distress/bleaching within hours).

So, as Tamberav and a few others I’ve seen here on the forums can attest, 86 may not be too hot, but - personally- if you’re going to run a tank that hot I’d take things nice and slow (likely ramping up over the course of a month or two) to get the corals there as a precaution.