Heat question

[jc]

O.k. I installed some fans on my tank hoping to get the temp down. Two fans in the hood, one in and one out and one fan on the fuge pointing down at the submerged pump. My temps went from 81 to 80. At this point what is heating my tank? my Lights are t-5's which are about 6" above the water. My pump is a mag5. Could my heater be malfunctioning? It is set at 75 degrees.

I'm in the process of finishing the setup on my 180g. Yesterday I put in 2 300w heaters, one in the sump and the other behind the overflow. This tank is also at 80 degrees. My question here is what temp do I set the heaters at? Is it bad to have the temp drop too low at night?

Both tanks are at 80 degrees but my A.C. is set at 75.

[matt]

Pumps, powerheads, lights...they all add heat.

[hobogato]

my tanks are running around there right now also, and they usually run 77 to 79, i think it has to do with the high humidity lately and the tanks not being able to cool thru evaporation as efficiently.

[dwdenny]

it could be the heaters. on a big tank I would think about running them on a dual stage controller so that there is a double protection. The controller will shut them off at 79 or if that fails then the heater can shut it off at 80. hth the fans should help. big swings in temp is not good at all. what to keep temp swings more then 3 degrees to a minimum.

[jc]

I think i'll measure the temp at night with the heaters off and adjust them for a no larger than 3 degree drop. What is the temperature of the ocean where most of this stuff comes from anyway?

[hobogato]

i think the average is around 78 - 79.

[jc]

78-79! Then why am I so worried? That's what my **** fish get for living in Texas.

[hobogato]

people who keep lots of SPS corals usually try to keep their temps closer to 77 because heat is supposed to be a major factor in RTN. i have heard of people that have SPS among other things with tank temps routinely 83 or even higher with no problems.

[GaryP]

I would also suggest having both tanks blowing in. When the fans blow out they have a tendency to build up salt and don't last as long. Having both blowing in does the same thing. The idea is just to get lower humidity room air into the hood to increase evaporation and cooling, as well as to break up the layer of super humid air at the water surface.

[TheOtherGuy]

people who keep lots of SPS corals usually try to keep their temps closer to 77 because heat is supposed to be a major factor in RTN. i have heard of people that have SPS among other things with tank temps routinely 83 or even higher with no problems.

Yep! Tank ran at 87-88 for 2 days last week in the afternoon. Lost 2 Acros and couple more are still not happy but I think they will be ok. Heat will take them out quick.

I now have 2 fairly large fans mounted and blowing down on the tank. Temp now staying around 77 (maybe 78 in the afternoon).

As mentioned before do not trust digital thermometers too much. I have 2 digital thermometers on my tank right now and both read different temps.

Been meaning to bring home a floating mercury thermometer to see which one is correct. One reads 1.5 degree higher than the other. Probably not a big deal for air temp but for a reef tank it could be the difference. You know is it 82 or 83.5???

Also keep in mind higher temp means less O2 in your tank. Add if by chance your salinity is a little high too then even less O2 in your tank.

[GaryP]

I think adding moving air may also help with gas diffusion at the water surface as well. Slightly off topic, but related to the discussion here.

[TheOtherGuy]

Gary - Yes Perhaps. I know fans help with my gas diffusion. LOL.

Anyway....

I just know if the fans do not do the trick for me then either I quit doing Acros in my tank or a chiller is in the future. Oh and the fans I have are not small fans they are fairly large and are moving some air. One runs all the time and the other comes on when the lights come on. According to one of my digital thermometers and min/max memory, my tank is now only varying 2 degrees over the day, 77-79 and that is a whole lot better than last week 79-87 YIKES!.

[jc]

I noticed that my digital thermometer is reading 80.5 but my cheapo metal thermometer is reading about 78.
Not that big a difference but still.

[TheOtherGuy]

Yes these digital thermometers seem to be off sometimes. At least the inexpensive ones. I brought home a good old fashioned floating mercury thermometer. I shall put it in my tank and see which thermometer is telling me the truth.

2.5 degrees may not seem like a big deal but...... If your tank is over heating or close to over heating the difference between 82 and 84.5 could mean the differenence between life and death especially for SPS stuff.

I still have some SPS that are recovering from my 3 day overheat. My tabletop which was doing just awesome (until last week) has RTNd a bit but is hanging in there. Only time will tell.

[GaryP]

Its not actually a mercury thermometer. They use alcohol with a red dye. Sorry for the interruption.

[GaryP]

Mark, I am using 4 X 100 cfm fans on my tank.