Tank Temp

Question
QUESTION: I am concerned about the temperature in my 100 gallon saltwater tank. The tank is 6 feet long and I am using a 48 inch 4 bulb (54 watts each)on the tank. I have 2 250 watt heaters in it. I had the heaters set to keep the tank between 75 and 78, but we have not had the air on consistently and the temp in the house has gotten to be a little above 80. The temp on the tank has gotten as high as 83.7. It was back down to 82.4 this morning.   I know that soon we will be leaving on the air soon. I am not sure what to do. I am afraid to turn the heaters down incase we have a cool spell. Any suggestions or do I not need to worry?

ANSWER: Hello Debbie,

Leave the heater where they are. They wont come on unless they need to.  (you can verify if they are off, by either touching them, or looking at them, if they have an internal light)

But, assuming they are operating like they should, they shouldnt be a problem...

Do you have covers or glass lids onthe tank?  If so, take them off.

Do you have a sump?  If so, put a fan down there so it blows across the surface.

Do you have a canopy on the tank?  If so, open it up during the daytime, and put a fan up there so it blows across the water surface.

The evaporation willincreas dramitically.  But, the temperature will drop at least five degrees

so, you will be adding more water each day, but your tank will be cooler.

You probably should invest in a chiler to make sure that everything works well, and stays cold, but even with a chiller, i would still reccomend the fans, to reduce the amount of time the chiller is on, ($$$ - electric bill???)

It is cheaper to run fans then chiller, but, having a chiller for those days that th fans cant keep up is a good insurance policy if you can afford the chiller.


BTW: running the AC just to keep the tank cool is expensive


Also, i am guessing your room temperature is warmer then you believe if your tank is getting up to 84

Good luck and please let meknow how things work out for you

---------- FOLLOW-UP ----------

QUESTION: Actually, we would not be running the air just to cool the tank. My husband works at home and we are already having 80+ degree days here in the south.  
The temp was down to 82 when I got home a little while ago, but then again the air has been on all day.
I actually do not have a glass top, I have plexiglas because I have the six foot long tank and it did not come with a top. The plexiglas is about 1/8 inch thick. I ttok one side off. I left the side under the light on.
I do not have a sump.
I appreciate your help.

Answer
I answered thiss earlier but seeitagain, so not sure if you got it or not...

Remove the plexi glass lid. (unless you have jumping fish)  And if you do have jumping fish,you have to get 1/4inch mesh screening instead.

The plexiglass, or regular glass or anything really, blocks light.  It will reduce the light at least 30%, AT LEAST.

It can be measured with a PAR meter.  that is important.  That is like saying, you dont want corals onthe bottom half of your tank.

Or,why have powerful llights when you can get and use less powerful lights.

Place a fan so that it blows across the surface of the tank.  this will drop the temperature 5 degrees or so.

You will evaporate more water but your tank will be nice and cool.

I would research buying a chiller.  I know they are pricey, especially now, but, they are great insurance policy so that you dont loseyour corals.  It is easy to lose corals above 84+ degrees

Even if it didnt get that hot, corals wont thrive and will stagnate and not groww at temps above 81 degrees.

Wide swings, 78-82 is the outside peramter I would want...  My tank is around 77.8-80.2 degrees...

I like to stay within 2-3 degrees swing from night to day...

Please let me know what you end up doing...

Good luck

bill