THE MARINE FISH AND INVERT REEF AQUARIUM

11. HEATING AND COOLING THE REEF AQUARIUM:

11.1 HEATING:

11.1.1 INTRODUCTION:

The temperature of the tank's water determines the metabolic rate of all animals that are in it. When the temperature fluctuates too much and too rapidly, many lifeforms kept in the tank will suffer. Fish, in particular, adapt their body heat to the ambient heat, unlike humans. This reduces the span of temperatures that are life sustaining greatly. Whereas humans can take great temperature variations, fish and corals cannot, and will die if you do not adjust the temperature of your tank correctly.

Temperature changes of smaller magnitudes must be avoided as well. Parasitic disease outbreaks are not uncommon when the temperature is changed quickly, either upwards or downwards.

Many a hobbyist has experienced this already, often with loss of lifeforms because parasitic diseases are so hard to eradicate even in fish-only tanks, let alone in reef aquariums where copper or quinine based medications cannot be used.

Because the lifeforms kept in reef aquariums are quite sensitive, not as resilient as their fresh water counterparts, changes that the hobbyist considers minimal in a fresh water tank do not apply in reef aquariums. A variation of 2 deg Fahrenheit can be enough to cause problems. This must be kept in mind when, for instance, making water changes. Always make sure that the water you add is of the same temperature as the one already in the tank.

Around natural reefs the temperature never varies very much, and when it does it varies very slowly. Keep that in mind as well. Do not make temperature changes rapidly. If your tank is now running at too high a temperature and you take steps to reduce it, which you should, make the changes slowly. Don't go from a present 82 deg to a new temperature of 76 deg in a matter of hours. You are guaranteed to have problems if you do.

Depending on where your animals came from, and more likely than not they will have come from Indonesia, Hawaii or the Philippines, they are accustomed to temperatures in the range of 75 deg to 77 deg most of the time. For short periods of time these temperatures may be lower or slightly higher, for example as low as 73 deg and as high as 80 deg.

Short periods of time do, unfortunately, not mean days or continuously. Too high temperatures, maintained for too long, will damage the corals and will hurt other invertebrates as well.

11.1.2 CONVERSIONS:

Frequently, references to temperature, in books, magazines and so on, are in degrees Celsius rather than Fahrenheit. One reason is that many books come from Europe, and another is that the scientific community uses Celsius or Kelvin rather than Fahrenheit.

Converting from one to the other is simple. You have probably seen the formulas often, or learned them many years ago in school. For those in need of them, here they are again:

  1. Degrees Celsius = 5/9 (degrees Fahrenheit minus 32)
  2. Degrees Fahrenheit = 9/5 of Celsius, plus 32

Let's look at two examples: We want to convert 25 degrees Celsius to Fahrenheit, according to formula (2) the calculation is: 9/5 of 25, plus 32 or after calculating 77.0 deg Fahrenheit. How much is 82 deg Fahrenheit in Celsius degrees? Again, according to formula (1) this time: 5/9 (82-32), or after calculating 27.77 Celsius degrees.

To allow you to quickly interpret Celsius and Fahrenheit degrees, we are including a conversion chart of the temperature range that you may be dealing with when reading books on aquarium keeping. The chart allows you to go either way.

Celsius	Fahrenheit	Fahrenheit	Celsius 
19			66.2		66	18.9 
20			68.0		68	20.0 
21			69.8		70	21.1 
22			71.6		72	22.2 
23			73.4		74	23.3 
24			75.2		75	23.9 
25			77.0		76	24.4 
26			78.8		77	25.0 
27			80.6		78	25.6 
28			82.4		79	26.1 
29			84.2		80	26.7 
30			86.0		81	27.2 
					82	27.8 
					83	28.3 
					84	28.9 

Many aquariums are kept at too high temperatures, and many animals are lost as a result. Often the hobbyist does not even want to admit this fact to himself or herself, and will try to make everything in the tank look good, even though the temperature is way out of control. Such is, I am afraid, not possible.

Calling manufacturers and asking many questions in an effort to make such tanks work is really a waste of your time, especially if you do not admit the fact that the temperature is far above what it should be. Of course, hobbyists realize that when they admit to such high temperatures the answer is simple: lower it first, and things will get back in control.

Some animals are even more sensitive than others, as some hobbyists may have found out about, for example, carpet anemones. If you cannot keep them alive, suspect the temperature.

11.1.3 WHERE DOES HEAT COME FROM?

Excess heat in the aquarium can have several causes that the hobbyist can possibly eliminate without incurring great expenses, usually buying a cooling unit.

A few that are easy to solve, or at least less expensive to solve than buying a cooler are:

If you cannot solve your temperature problem by changing pumps, or by installing fans in the lighting hoods, you may be in a quandary that can only be resolved by installing a cooling unit.

Cooling units cost from $500.00 to several hundreds more, depending on size, and because they are compressor operated, consume a fair amount of electricity as well. Try to solve your problem otherwise if you can.

Changing pumps, or installing fans in your light hood is much cheaper than buying a chiller. Seriously consider it if you have to.

11.1.4 HEATER TYPES:

Many hobbyists do not have a heat problem and need to provide supplemental heating to their tank. Such is easily done by installing one or more bayonet heaters in the sump of the trickle filter, depending on how much heat needs to be generated.

Because bayonet heaters can stick, meaning stay in the on position, I always recommend the use of several, rather than just one, especially if you need a fair amount of heating. For example, I would use three 50 watt heaters, rather than one 150 watt. Since it is unlikely that all three will fail at the same time, and since 50 watts cannot do as much damage as one 150 watt heater, I find such much safer.

Bayonet heaters, also called stick heaters, come in various finishes: plain glass tubes, glass covered with silicone, glass covered with a protective cover, ceramic, Teflon*, stainless steel, and so on. Your budget determines which one you get. I prefer the Teflon coated ones because they cannot break in the sump, but they cost a great deal more. So do the stainless steel ones.

If the heater you acquire does not have a built-in temperature on/off regulator, you will have to install a separate one to allow you to adjust the set point. Temperature controllers, similar to the units existing for pH and redox, are also available from certain resellers and from the catalog companies already mentioned.

When it comes to heaters, accuracy in the on and off switching is key. Such is also the reason you should buy a well known brand, not some cheap knock-off. You have too much at stake. Don't let an extra $20.00 for a good quality heater endanger the life of the animals in your tank. Believe me, cheap heaters will stick.

Besides using Teflon units, I also like the German Ebo-Jaeger units a lot because they are submersible, adjustable, accurate, and covered with a protective layer so the glass is not easily shattered.

Cable heating is yet another and a more stable form of heating and mainly so because it spreads the heat much more evenly throughout the tank. Unfortunately the cables rip easily because of rocks and bully fish, urchins and so on. At Thiel*Aqua*Tech we are working on the development of such a system that holds up better in reef and freshwater plant tanks. Unfortunately it is not ready, and no date for its introduction is available at this time.

11.1.5 MAKING AN INEXPENSIVE COOLER:

Rather inexpensive coolers can be made using a small second hand freezer. Many hobbyists have tried it and they work fairly well. One can reduce the temperature about 4-5 degrees if the system is properly set up, and if metal type tubing is used to conduct the water in and out of the freezer.

You must run water very slowly through a small diameter tube that enters the freezer somewhere through a hole you have to drill through its side. A coil on the inside ensures that the water remains inside for a certain amount of time. The longer the coil, and the slower you flow the water, the better cooling effect you will get.

Another hole needs to be drilled through the side for the tube to exit again. Water is pumped through the tube by means of a very small pump, maybe even a small power head pump. Alternatively, use water from a bypass on the main water return line, the one going back to the aquarium. This will require that you glue a Tee-fitting in-line, and then bush it down to the size of the tube (hose) that you are using. After you have passed the coil through the holes you drilled, isolate the inside of the unit by applying a liberal amount of aquarium silicone around the holes, both inside and outside the freezer.

Because certain types of material inhibit heat exchanges, e.g. plastics, the best cooling effect is obtained with stainless steel tubing. You must use 316 SS, as other types will not resist salt water for very long. Copper can, of course, not be used. Another metal that is safe, but much more expensive, is titanium.

Since you are pushing warm water through the freezer unit all the time, it will run just about continuously. This is a major consideration in terms of electric consumption.

11.2 COOLING UNITS:

The best way to cool the tank if the temperature is too high, is to use a chiller or cooling unit matched to the size of your tank, and the number of degrees you want to lower the water temperature.

Cooling units are fairly expensive by hobby standards, but if you absolutely need one few alternatives exist as we have already seen. Several companies now offer such equipment and advertise in magazines such as FAMA: Aquanetics, Aquarium Sales and Service and TAT. Call around before buying. Prices can vary quite a bit.

Investigate all other avenues open to you first, and if none bring the temperature down enough, consider getting a cooler if you are really interested in making your tank look much better, because it will make a big difference.

Whichever way you go, keeping the tank at the recommended temperature is yet another important aspect that you have to attend to. Trying to run the tank at far too high a temperature will not work, and will end up costing you more money in the long run anyway, not to speak of all the animals that will have been killed in the process.



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