I found the following on the Marine Depot Reef forum -- I thought it was very informative. I personally think the comments about lighting are very thought provoking. Hope it's okay to post this -- if not please let me know.
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I have noticed with my tank that on cooler days the maximum temperature gets to 81f when the lights are on, and remains there for the lit period. It seems that no matter how long the lights are on, the latent temperature of the room air and fan doesn't allow the temperature to rise above this. Therefore you could say this is 'tank temp max' at that room temp.
When the room is around 81f the 'tank temp max' becomes 83f, rising from 80f. On very warm days the 'tank temp max' becomes around 85f.
These temperatures seem high, especially compared to the 78f that some people chill their water to when using a chiller. However, my research (web) has found that in nature the average summer temperatures of most natural reefs are in the 82 to 85f range.
What I am proposing to do is raise my minimum temperature to near my 'tank temp max' of 83f. Then if the maximum temp rise on a warm day is only 85f, the corals will be accustomed to this higher range and will not suffer any signs of stress.
What this theory relies on is the fact that the maximum temperature point is not reliant on the starting temperature but on the other factors in the room such as the fan etc, therefore not letting the tank temp rise above 'tank temp max'. If that were the case then this plan would seem more energy efficient, cheaper and closer to nature than using a chiller!
Has anyone had any experience with this theory?
If so, did you rise your minimum temp up slowly over time to avoid any shock?
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The indo-pacific reefs do on average run 82 and above which is where the majority of the corals and fish we keep come from. Being ectotherms, it makes no sense to me to keep such animals in the 70's. Having kept track of the reef temperatures for a number of years now in the Phillippines, I can say without a doubt that the coral reefs that average 30-60 foot depths run at a night time low of 82-84 depending on daytime cloud cover with daytime highs running 84-88, again depending upon cloud cover. In fact, last night during a night dive at 8pm at 60 foot deep, the temperature was still 86. Also of note, I see a great many coral species in the shallows (3-6') deep near and within the sea grass beds that see daytime high temps at 90 and above, so warm, that I find it uncomfortable myself while wading out to deeper water.
If your corals have been acclimated / accustomed to lower temps, you would of course want to very slowly acclimate them back to their natural environment, by slowly, raising the temperature by one degree per two to four weeks untill you reach your daytime high target level. Which 85 would be just fine. Unless of course you are keeping species that come from outside the indo pacific region such as Australia and the Caribbean.
My reef system never sees temps below 82 and with the four hours of a metal halide running, it can easily reach 86. Once it reaches that mark, I then add a frozen soda bottle to the sump to keep it from going past 86 even though I regularly see 88 on the wild reefs. I take this action simply because I prefer the tank to have a bit of wiggle room and not push my luck.
Off topic a bit here, but I also see no reason to run metal halides for the full 12 hour photoperiod that our reef tanks should be getting (unless thats the only type of light system you have, but would consider another approach). With the sun's angle at sunrise and sunset as well as light blocking landscape features, I know of no wild corals that get 12 hours of "high noon". At best, maybe six hours, but on average, probably closer to about four hours. Which is why my light system is now geared to where half of the CFs (household compact fluorescents) come on at day break (6am), two hours later the remaining CF's kick on, and from 11am untill 3pm the metal halide is burning. At 5pm half of the CF's turn off and at sunset (6pm) all lights are off.
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I have noticed with my tank that on cooler days the maximum temperature gets to 81f when the lights are on, and remains there for the lit period. It seems that no matter how long the lights are on, the latent temperature of the room air and fan doesn't allow the temperature to rise above this. Therefore you could say this is 'tank temp max' at that room temp.
When the room is around 81f the 'tank temp max' becomes 83f, rising from 80f. On very warm days the 'tank temp max' becomes around 85f.
These temperatures seem high, especially compared to the 78f that some people chill their water to when using a chiller. However, my research (web) has found that in nature the average summer temperatures of most natural reefs are in the 82 to 85f range.
What I am proposing to do is raise my minimum temperature to near my 'tank temp max' of 83f. Then if the maximum temp rise on a warm day is only 85f, the corals will be accustomed to this higher range and will not suffer any signs of stress.
What this theory relies on is the fact that the maximum temperature point is not reliant on the starting temperature but on the other factors in the room such as the fan etc, therefore not letting the tank temp rise above 'tank temp max'. If that were the case then this plan would seem more energy efficient, cheaper and closer to nature than using a chiller!
Has anyone had any experience with this theory?
If so, did you rise your minimum temp up slowly over time to avoid any shock?
*******************************************************
The indo-pacific reefs do on average run 82 and above which is where the majority of the corals and fish we keep come from. Being ectotherms, it makes no sense to me to keep such animals in the 70's. Having kept track of the reef temperatures for a number of years now in the Phillippines, I can say without a doubt that the coral reefs that average 30-60 foot depths run at a night time low of 82-84 depending on daytime cloud cover with daytime highs running 84-88, again depending upon cloud cover. In fact, last night during a night dive at 8pm at 60 foot deep, the temperature was still 86. Also of note, I see a great many coral species in the shallows (3-6') deep near and within the sea grass beds that see daytime high temps at 90 and above, so warm, that I find it uncomfortable myself while wading out to deeper water.
If your corals have been acclimated / accustomed to lower temps, you would of course want to very slowly acclimate them back to their natural environment, by slowly, raising the temperature by one degree per two to four weeks untill you reach your daytime high target level. Which 85 would be just fine. Unless of course you are keeping species that come from outside the indo pacific region such as Australia and the Caribbean.
My reef system never sees temps below 82 and with the four hours of a metal halide running, it can easily reach 86. Once it reaches that mark, I then add a frozen soda bottle to the sump to keep it from going past 86 even though I regularly see 88 on the wild reefs. I take this action simply because I prefer the tank to have a bit of wiggle room and not push my luck.
Off topic a bit here, but I also see no reason to run metal halides for the full 12 hour photoperiod that our reef tanks should be getting (unless thats the only type of light system you have, but would consider another approach). With the sun's angle at sunrise and sunset as well as light blocking landscape features, I know of no wild corals that get 12 hours of "high noon". At best, maybe six hours, but on average, probably closer to about four hours. Which is why my light system is now geared to where half of the CFs (household compact fluorescents) come on at day break (6am), two hours later the remaining CF's kick on, and from 11am untill 3pm the metal halide is burning. At 5pm half of the CF's turn off and at sunset (6pm) all lights are off.
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