Saltwater aquarium fish

Wed Feb 20 15:54:31 UTC 2008

The stable temperature is very important for a marine tank. Fish from the sea are accustomed to stable temperatures because the sea is such a huge mass of water and the temperature, especially in the tropical seas, does not change, or it changes, but only very slowly. Mostly because of global warming or cooling. Salt water tropical fish in an aquarium can stand changes of the temperature if they are happening slowly and the temperature rises or falls only by a few ?°C, so you don’t have to be scared if the temperature falls a bit during some occasions.



Almost in every country you will need a heater for your tropical salt water aquarium. Only in a few countries the winter is so hot that you will not need any. On the other hand, you will not need any aquarium heater if you want to own a tank with fishes from cold water seas.

You are given more options how to heat your tank. The most common is a normal heater which looks like a stick and you immerse it into the water. The problem with this kind of heater is that it has to be really properly isolated from the salt water. If water finds it’s way into the heater, you can throw it out (but don’t forget to recycle it). Salt water will rust and destroy everything which is not resistant enough. Metal, even rustles steal and rubber will be destroyed very quickly. Only plastic and glass are the best materials for a salt water tank. The best is to read the instructions given by the manufacturer and use it only if is written there that such heater can be used for salt water aquariums. If anything goes wrong, at least you can say that within the product’s guide it is written that the product can be used in salt water and you get your money back, of course if the product was damaged by the salt. Also you may use a freshwater heater too and cover the metal parts with plastic, but it is more risky, because you may not cover the heater correctly and the water will damage it. In the worst case the isolation of electricity may be destroyed by the salt water and it may kill your fish, and if you put you hands into the tank, to see what is happening, or to take out the dead fish, it may kill you too! If it is used as it should be used, it is my favourite type of heating the tank, because it has a thermometer and you can choose on which temperature you want to have the water heated. If the temperature is higher, the heater will shut down, it will save money for electricity, and the best of all, it will keep the temperature stable. Another advantage is, that there is no heat loss, because the heater heats just the water. Because of the effective and easy use, it is the most common used heater both in freshwater and salt water tanks.

On the market you may find many types of these tank heaters. They have different wattage, so which one should you choose? It depends on how large is your tank. Some say that if you have only 90 litre aquarium then you need almost 1,7W per litre, so you will need about 150 watts, for about 200 litre big tank, you need about 1W per litre and for more litres, you need less than 1W. However it depends on how fast you want to increase the temperature and also on the temperature of the room (if the room temperature is 15?°C then you need more powerful heater than you would need if the temperature was higher than 20?°C) For example if you set up the tank and it already has about 20?°C, you will not need a very strong heater. In this case for a 90 litre big aquarium you may need only one 50W small heater. For bigger tanks you may use two small heaters too. If your aquarium demands 100W, you may use two 50W heaters and situate them to the opposite sides of the tank. If you heat the tank it this way, the water will be heated in a more balanced way.

If you are using this type of heating your marine tank, you should be careful when you are changing some big amount the water. If you pump out the water and the heater is still on, the heater will heat more, because it wants to heat up the whole room. Then if you pump back the water, and the water will have lower temperature and when the cold water gets into the contact with the hot heater, the heater may, and there is a big chance that it will, break. So you have to shut down the aquarium heater every time you are changing the water. Also you may get burnt if you touch the heater. Then you should turn on the heater correctly. It should not be in contact with the gravel, because it may heat it up and some salt water fish and creatures which live in or on the gravel may get burnt.

Then you can use an under-gravel heater. It is also effective and there are no losses of hear, however it is not practical. If something goes wrong and the heater will not work any more, you will not have any other opportunity, only to take it all out from the gravel and fix it. This can be very stressful for the fishes, because you have to remove all the decoration, caves, rocks and plants too. Also there can be problems if you are using under-gravel filtration system with under-gravel heating. And of course, it also has to be salt water resistant too.

Occasionally you may find some heater pads. This type of aquarium heater is very specific. It comes under the tank and it heats it from the bottom. It looks like an electric blanket which you may use at home, you just place it under the aquarium. There are no problems regarding the fact f the heater is waterproof or not, and the salt water will not destroy the equipment. However, if the aquarium sprung a leak, it will be lost. On the other hand, the last thing on your mind will be a loss of the heater if such situation occurs. As always, there are some disadvantages too. This type of heating is not the most effective, because it will heat the glass, the stand but also the air, not only the water. Another problem is that if the pad brakes down, you have to lift up the whole tank if you want to repair it, or change the pad.

At last I am going to write something about the method of heating which is based upon the temperature of the room. You heat up a room where the tanks are and the hot air will heat the tanks too. This method has it’s advantages and disadvantages. Advantages include that you can heat the tank without using any heater immersed into the water, so you don’t risk the break down caused by salt water. Also it is possible to heat up more tanks, not only one, and this method is the best for heating more than one tank. It is used mostly by breeders, who have a whole room full of salt water, or freshwater fish. The disadvantages are that you lose a lot of energy while heating up the whole room and the energy is not cheep today, so you have to choose a small room, maybe without windows too. You see that in such case the tanks could not be in the middle of the living room where you could watch them all day round. Then the room has to have a hight temperature and it is not very comfortable to work or watch the tanks when you feel hot and you sweat.

The best is to control the heating process by thermometer. You can choose from thermometers which may be stuck to the glass, or those which are placed in the water. External thermometers may not show the right temperature because they are influenced by the temperature of the room. Internal thermometers may break in the tank, so you should by such thermometer which have a safe filling, like alcohol thermometers. If you have a deep marine tank you should have two thermometers. One near the surface on the one side of the aquarium and another one near the bottom on the other side. It is because of layering of the heated water. You may experience the problem when the circulation of the water is not sufficient and the hot water is at the surface only, and on the bottom of the tank there is cold water only. Also the thermometer shows if the water is heated normally. If the salt water aquarium heater or heaters will not work as they should, you will spot it on the marine thermometer, so that you should keep watching them every time you are controlling the tank.

When we are speaking about heating of a salt water tank, maybe I should mention the isolation of the aquarium too. A good isolation is what will save your money because it will avoid losses of heat. Maybe I could recommend you to use polystyrene on the back and on the sides of the aquarium, of course from the outer side, do not put the polystyrene into the water, and let only the front glass free, so you can see what is happening in the tank. You may add an aquarium background on the polystyrene, so the tank will look like it was in the sea and that is has no end. You should not keep the marine aquarium open as well. The heat will go up and you will lose it that way. However, aquarium hoods are isolated usually, of course with some openings for the aerator, so that fresh air can be absorbed into the tank. The best isolation is to have the largest aquarium you can have, because the more water you have, the slower will the water cool down. So if there is an electricity outage, the water will keep it’s temperature for a longer time.