Is my tank too cold?

[tmelhiser]

I've never run into this problem before, but my tank actually requires the heater.

In my old 29g BioCube, it was all I could do to keep it below 80. My 40g Display Tank, with a 250W MH and 3 39w T5's, stays at 76.5 (according to my coralife digital thermometer) and my sump stays at 78 according to the Finnex 300w digital heater. I attribute it to the 2 120mm fans blowing across the surface at a total of 128cfm (at a near dead silent 14Dba).

So I've started wondering, which of these two gauges is correct? So later today, I am going to drop the coralife thermometer down in the sump and see what the readings are. If both are correct, what do you do then? Can you really have a 1.5 degree heat exchange from the sump to the display? And if so, is it OK to run the sump a little warmer to keep the display at the right temp?

In any event, what is the recommended temperature these days? I know it depends on the part of the world the occupants came from, but like most of us here, there are species from the Indian Ocean, some from the Red Sea, others from the Caribbean, maybe even a few from the Pacific Reefs.

Since I've always been fighting to keep the temp down, I've never really had to ponder "what if I could choose my own temperature". Perhaps this also means I now have the obligation to be a more conciseness selector of inhabitants and choose a region to specialize in?

So my summation quandary looks like this:

What is the best median temperature to keep the most diverse and healthy habitat and what habitat has the most bio-diversity to specialize in?

-t

[Brooks]

76-81 seems to be the most ideal temperature. Stability is key here, though. Try and adjust your heaters/thermostat in your house to keep your tank at a steady temperature, or as close as you can to steady.

[tmelhiser]

Right now the temp swing is about 0.5 degrees from day to night in the display tank according to the coralife thermometer in it.

The really big shift is from display to sump.

I am just about to measure it. This way I know what the difference between the finnex heater and the coralife thermometer actually is and how to read the two.

My hope is that when I drop the coralife thermometer in the sump it reads 1.5 degrees cooler than the heater digital display.

The down side to this is that if it's the case, then I need a third party arbitor to decide which one is the accurate temp.

-t

[Jimbo]

My experience with those coralife digital thermometers is that they are almost always off. Take it and place it in a glass (or cup) filled with ice and just enough water to float the ice, read the temp after about 5 minutes. The temp should be just above 32. My bet would be that it is not. You can use that to make an approximate adjustment (+/-) to find out your real temp.

But, Brooks has it right. Stability is key. This time of year, mine is running between 77-78.

[tmelhiser]

Ok, finished with the tests... isn't time-lapse reading wonderful.

The result was that the coralife thermometer reads exactly the same temperature in the sump as it does in the display. I let it stay there for a good 10 minutes, but the result stayed constant, 76.1 degrees, same as the display tank before I moved it.

Take it and place it in a glass (or cup) filled with ice and just enough water to float the ice, read the temp after about 5 minutes. The temp should be just above 32. My bet would be that it is not. You can use that to make an approximate adjustment (+/-) to find out your real temp.

Off to use some ice as my constant. I am already safe in saying that there is a 1.5 degree difference between the two gauges. Now to find out which one is right.

By the way, what thermometer are you guys using to determine your temp?

-t

[Jimbo]

By the way, what thermometer are you guys using to determine your temp?

-t

I have a floating glass thermometer...can't remember the brand. I also have a sinking glass one in the frag tank in the garage. Both read the same, and that just so happens to be the same temp that registers on my chillers controller.

By the way, when I did the ice test, I found my old coralife to be 4 degrees too low.

[tmelhiser]

As I am watching the results of the "Ice Test", I am starting to remember the temps in my BioCube.... JEESH! If I was seeing 80 - 81, sometimes peaking at 82, on the display during the day? if it's actually reading 1.5 - 2 degrees cooler that the real temp? Those poor guys were almost at the boiling point... reaching almost 84!

Two minutes in, the reading is currently at 30.5. A solid 1.5 degrees colder than freezing, yet the water is still liquid (I am guessing the laws of physics haven't changed today).

30.3 and holding.

One minute left.

OK, 5 minutes in: 30.1

So the fact that the water isn't froze over means we are at an equilibrium. Even if the liquid is only 32.001 degrees, this puts the coralife thermometer off by a minimum of 1.899 degrees, if not more.

I will take the Finnex as the more accurate temp since the 1.8 addition tends towards the Finnex readout. I still maintain a 0.5 swing from day to night. The OCD side of me would like to see that worked out, but well within tolerance limits.

So it looks like 77 is going to be where I try and keep things. We'll see what the Texas summer has to say about that!

-t

[stoneroller]

I keep my display at 78. At 79, the Ranco temp controller turns on a fan. It cools until the tank hits 78. I have a Coralife digital for ease in reading as my controller is mounted behind the tank.

[Jimbo]

It looks like you have it under control. .5 degree day to night is not bad at all.

[barderer]

I have heard many bad reviews of those coral life digital terms too. Did you check against a glass term?