tank temp aint comin down


New member
i have a fan that turns on with the MH... my tank temp is at 82 in morning, and maybe 84 afternoon. one of my xenia has melted the other 2 are fine.... the corals are looking good also. this is with the heater OFF.

will adding another fan to run 24/7 do the trick? how much electricity will it use?


New member
try pointing a fan directly at the water, it will cool it due to evaporation so make sure you top off more often. another reason could be the temp of the room, if it's too hot in your room and your just using fans, you might not be able to do anything with just FANS. you may need a chiller.


Premium Member
i dont' think clip on fans are going to cost that much at all to run. A clip on fan may be around 20-30 watts? Only thing is with a fan, you have a lot more water evap.


Staff member
RC Mod
Run the fan constantly until you get it under control. Take off all lids including sections of sump.


New member
here is what i did...

get a vornado fan cheaper than a chiller but expensive for a fan...about $70.

point it INTO the sump as close to the water surface as safety will allow it. dont get shocked, dont die and i am not responsible for anyone trying this...

this is my lr holding tank connected to my main system and the fan is 3 inches from the water surface. a temp controller kicks in at 78 to turn it on. this fan keeps my approx 350 total adjusted volume system below 80F 99% of the time even with my equipment in the very hot garage. if the temps creep to 80, another temp controller kicks in to start my chiller...but it rarely comes on. i heard the chiller go on the first time sunday which was about 4 very very hot days in a row with temps here creeping up near 100.


Active member
Make sure you put the fan on a GFCI outlet. My fan accidently fell in my sump and luckily my GFCI tripped.

Clipon Fans are not very energy efficient. My 12" Fan uses half the watts and moves twice amount of air to a clipon fan


Active member
<a href=showthread.php?s=&postid=7511205#post7511205 target=_blank>Originally posted</a> by supernareg
i dont have place to put a 12 inch fan

When the lights go out you could open your canopy and just use any fan to blow it across the water. I had a 20 gallon tank that hit 84 last week. As a test I put a 12" fan on top of it and set the fan speed to medium. In 45 minutes the temp dropped to 78 degrees. The room temperature was 85 degrees.


Master of the 16 hour day
Team RC
You should also try running your lighting later in the day on into the evening. If you can, open your house up in the evening to help cool the house and improve air flow. This helps remove some of the humidity, allowing the tank to evaporate a little more and improve cooling.


Premium Nonpaying Member
try and cool your tank at night... keep the heaters off run you lights later in the day and raise them off the tank to about 10" i did all that and my tank went from 83(when my lights turn off) to 80 all day even with all the heat the passed few days...


New member
hehehe I still have mine at 77F.

You guys dont need heaters right now.

My lighting period is from 2:0pm to 11:00pm, and my room is the first to get sunlight in the mornings.

So by 2:00pm the sun is hitting the top almost the other side of the houseand there is nice shade on my side. All was planned well before setting my tank up because I cant afford a big chiller.



In Memoriam
light your tank during the cooler hours of the day also the cheapo fan from walmart poited right at your sump will cool tank easily 2-4 degrees


New member
I have a 58gal + 10gal sump with 400W MH lights. I run the big light from 1pm to 9pm, though I am going to adjust that shorter and later in a few days to compensate for the weather. I have four small computer fans on my MH fixture to evacuate the excess MH heat. They do a great job. I also have two computer case fans on the sides of my tank blowing across the water surface. Typically on an 80-degree day, the tank will not exceed 82 in temperature if I have some windows open for breeze and shades pulled.

If things get worse, I also have a normal floor/desk fan that I turn on and point along the long side of the tank. This moves the air that's trapped between the tank and the exterior wall, which is hotter than the rest of the apartment. This helps significantly.

This last largest fan uses about 40W of power on maximum setting.


New member
Mine's been running consistent 80-86 degrees since three weeks ago and everything is still doing great. Just a fan in the sump constantly on though! Occasional frozen water bottles in sump to get rid of some heat.


New member
Think of equilirium....

If your room temp is 82F and your tank doesn't have a chiller, no matter have many fans that you have, your tank's temp will not be below 82F.


Active member
<a href=showthread.php?s=&postid=7524642#post7524642 target=_blank>Originally posted</a> by gps
Think of equilirium....

If your room temp is 82F and your tank doesn't have a chiller, no matter have many fans that you have, your tank's temp will not be below 82F.

I think you are wrong about that. The energy from evaporation of water cools the water. The fan is used to lower the temperature of water by using latent heat of evaporation, changing water to vapor. Think of the getting out of the pool with a slight wind.

My 20g tank temp was 85 degrees. Room temp was 90 degrees. A single 12" fan over the 20G tank (blowing across the water) dropped the temp to 78 degrees in 45 minutes while the ambient room temp was still 90 degrees.

Thats how swamp/evaporative coolers work as well