Temperature.

I am having a huge Temperature problem on my 40G tank, i have my power compacts 5 inches above the water, no hood so the heat is not being traped in there, the ac in my house is on all day at a temperature of 70 degress, and for some reason my tanks temperature was at 81-82 degres i had to go out and buy a big clip on fan and put it behind my lights and now in day time the temperature is stable at 77 but at night it goes from 75-79 huuuggee fluctuation in temperature my heater is put on at 80 so it doest let my fan bring the temp donw to who knows so guys please help me on this urgent matter.

 

Unfortunately the only way to keep the fluctuations down is a chiller. (very expensive) Or the fan setup you are currently doing. I found it was just easier to hook my fan up to the timer that my lights are on to cut down on the fluctuations. You can also read on the forum here that people use ice but that also cools the tank down slowly and will require more work on your part.

 

Wow, if your heater is at 80, no wonder why it's peaking 81-82. Set it to 76 to keep it in the 76-80 range. Are you sure there isn't another thing causing the overheat, say like a return pump or having it close to a window with direct sun light or the other?

 

No no my heater was at 76 b4 but when i got my fan it would drop my temperature way below 76 so i put my heater at 80 to fight the fan.

 

Hmm, my temp is steady at 80-82 during the summer. Most of my tank inhabitants are doing fine....but maybe thats why I'm having this Brown Jelly problem??

 

A dual stage temerature controller costs around $120(new), and will eliminate this problem along with alomst any temp fluctuation at all. It also provides protection from a heater sticking on like we have all heard about too many times.

Ranco controllers are pretty common in the hobby, and about the cheapest you will find. www.diyreef.com has them.

I use a digital aquatics reefkeeper.It is about $100 more than the ranco, but it has other features like light timers wave maker etc. http://www.saltycritter.com/controller-index.htm

 

I have to agree with jtReef that you should put the fan on the timer with the lights - so that it's on when the lights are on and off when the lights are off - that way it's not cooling it off too much when the lights are off, but keeping it cool when they are on. That's what I do and my tank these days (in our 90+ temps we've been having out here in Colorado) has stayed at a nice 78 to 79 degrees

 

You might also want to consider a stronger and better heater. There are heaters that dont cycle on and off as much to keep the temp at a steady state. I use titanium heaters and get very little or know temp fluctuations.
But I agree with the timer for your fan, its probably the simplest and safest thing to do.

 

I have my heater off completely now that it's hot and my chiller is on all day. I give my chiller a break during the night because it gets to hot. The water temp goes from 83F from over night to 78-79F all day. As long the temp rises and lowers slow, it should be fine. Don't forget in the summer, the ocean temp rises, peaks, and then lowers.

 

Temperature Stability

Hi I Would Suggest That You Use A Temperature Control Module.
I Live In England An Use A Module From A Company Called System 2000 In Batley Bought For Around 50 Pounds Sterling On Ebay.co.uk
This Device Has A Preset Temp Say 25 Deg Centigrade.
Once The Temp Rises Above The Fan Is Turned On Until Temp Is Reduced.
I Run My Tank At 28 Degrees Centigrade And Have Only Ever Had A Fluctuation Of Around 0.1 Degrees8)