Tuesday, February 28, 2012
Evaporation and Air Circulation
Evaporation, when water turns from liquid to gas, helps to cool aquarium water. Evaporation occurs with the addition of energy to the water, such as heat transferred from lighting, pumps, and the room’s air temperature amongst other things. In order for evaporation to occur, the water surface must have exposure to the open air. Plastic hoods and glass canopies hinder the amount of evaporation by limiting air flow and trapping the moisture and heat in the aquarium. Opening the hood or canopy, or removing it all together can help when you’re battling high temperatures. You can also increase air flow and evaporation with a small fan. Fans should be pointed to blow across the surface of the water, and can be a big help in drawing heat away from an intense lighting fixture. How many fans you need depends on the size of the tank, but even one small fan can make a huge difference. Cutting back on how long the lights stay on can also help by reducing the amount of heat energy put into the water.
Good water circulation is key to keeping the water cool. Heat energy dissipates at the water’s surface. Furthermore, gases exchange at the surface of the water; Carbon Dioxide leaves the water, and Oxygen is introduced. Without good circulation the water’s dissolved oxygen levels can become alarmingly low at higher tank temperatures.
So what’s considered good circulation? Circulation can vary from tank to tank depending on how the tank is decorated, the type of inhabitants you have, tank dimensions and more. Generally speaking, fish only tanks should have enough water flow to turn the water over about 10-40 times per hour (tph). Tanks with soft corals should be turned over about 10-30 tph. Mixed reefs (soft and hard corals) and tanks dominated by large polyp stony corals should be turned over 30-50 tph. Small polyp stony coral aquariums should be turned over at least 40-80 tph. These are simply rules of thumb and may not apply to every tank, but by having adequate water flow, the tank should naturally run cooler.
Break out the Ice
When worse comes to worse, ice can be a simple solution. Freeze water in clean bottles that have never been exposed to soap or other detergents. Don’t use ice packs as they can leak, and don’t throw ice cubes directly into the water either. Unless you’re using un-chlorinated water, you will be directly adding chlorine and/or chloramine to your tank water. Bottles are easier to take out when the temperature hits the right level. Let the frozen bottles float in the tank or in the sump. Be sure to monitor the temperature–there’s no easy way to control how much or how quickly the temperature in the tank will drop. While reducing the temperature can be imperative, it must not be done too quickly.
Employ a Chiller
If maintaining temperature is a big issue for you, it may be best (or necessary) to invest in a chiller. Chillers come in a variety of sizes and styles that can be plumbed in-line or placed in the sump. To buy the right size chiller for your set-up, you’ll need to know the size of the aquarium, and how many degrees you want to drop the temperature of the tank.
Understanding of how chillers are rated will also help you to judge which chiller to purchase. The easiest rating to find on a chiller’s packaging is the horsepower. Unfortunately, the amount of horsepower doesn’t directly equate to how much heat the unit will be able handle. The HP rating can be useful as a general guide or for determining how many watts the unit is going to use, but the better number to look for is the BTU (British Thermal Units) rating. Chillers are rated in BTU’s, just like air conditioners. More accurately, they are rated in BTU’s per hour (BTU/hr). A BTU essentially equals the amount of energy it would take to raise the temperature of a pound of water 1ºF. Chillers remove BTU’s (heat) from the water, so BTU/hr gives you a perspective of how much heat removal the unit will achieve within a time frame. While HP lets you know how much work the chiller will do, the BTU rating shows you how efficient the unit is. The higher the BTU rating, the cooler your tank will be.
There are many factors that will influence how the chiller performs including flow rate, tank size, and heat sources (lights, equipment, ambient room temperature). All of these things have to be taken into account when sizing the chiller up. Just because your friend’s ¼ horsepower chiller cooled his 75 gallon tank to his satisfaction, doesn’t mean it will be an efficient unit for your 150 gallon tank– regardless of what the manufacturer says on the box. As a very general rule, a 1HP chiller should be able to remove about 12,000 BTU’s at peak efficiency. From there, we can assume a ¼ HP chiller should be able to remove a quarter of 12,000, or 3,000 BTU; a 1/2HP chiller should do 6,000 BTU, and so on. Some models achieve better numbers than this, and some less. Ask a salesperson if you’re shopping for a chiller, we can tell you more about the options and help you buy the right chiller for your system.
Below is a guide as to what horsepower chiller you can use to drop the temperature about 10°F. Remember that different manufacturers have different BTU ratings for their chillers, and as such a chiller of one brand may outperform a chiller of another, regardless of their horsepower. It may be necessary to go to the next size up for larger jobs requiring more than a 10ºF drop in temperature. At the very least it’ll be more energy efficient to do so, as the chiller will have to turn on less frequently than it lower HP models. Be sure to check the packaging to see what flow ratings each manufacturer recommends as well.
Monday, February 27, 2012
First thing, know what the ideal temperature range is for the marine fish you keep. For example, if you keep fancy goldfish, you’ll want to maintain the tank at between 60 and 75 F. But goldfish can generally tolerate much cooler temps and daily fluctuations with ease. Neon tetras would prefer temps maintained at between 68 and 80 F, and may be much more sensitive to even slightly cooler temps and small fluctuations. Monitor your tank’s temps with a reliable thermometer and try to observe the changes in temperature through the day (and after the lights go out).
The standard means of heat regulation in the aquarium is with the use of aquarium heaters. 3-5 Watts per gallon is generally the recommendation for supplying adequate heat. However these heaters only increase the temperature of the aquarium a certain number of degrees. If the aquarium’s room is drafty or kept cooler than the rest of the house, 3-5 watts per gallon may not be sufficient or efficient to keep the temperature in the desired range. Performance of the heater depends on many aspects including wattage, the size of the tank you put it in (larger tanks may require multiple heaters to maintain even and consistant temps), and the temperature of the room where you keep the tank. Beware of vents, windows and doorways in the tank room. Frequent blasts of warm and cold air and consistant drafts can quickly impact an aquarium, especially smaller set-ups.
Remember that too much heat can also be your enemy. Particularly reef aquariums and those containing invertebrates must be monitored carefully (especially during very hot summer months) to ensure that the temps don’t rise to rapidly or stay too high for extended periods. Chillers are often employed by serious reefers to protect against high temps, but there are some other ways to keep a tank cooler if you can’t afford one. But even for saltwater and tropical species, higher than average temps of maintaining constant temps at the higher end of the ideal spectrum can have less desireable effects.
Many breeders believe that keeping certain species of fish in the lower range of their temperature tolerance is advantageous. Cooler temps can stop prolific pairs from spawning, preventing unwanted fry. It is also believed that the lifespan of your fish can be increased when kept in the low end of the temperature tolerance range, possibly even 2-4 times the normal lifespan. Growth rate also slows, but the longer the fish lives, the longer it will grow ultimately resulting in larger max size. Some aquarists swear they see reduced aggression in territorial species kept in cooler tanks. These tricks are not for the novice. Care has to be taken in maintaining this lower range; be sure to observe your marine fish carefully for any signs of distress. You may also need to adjust feeding amounts and frequency as their metabolic rates will likely drop and it can be very easy to overfeed.
Sunday, February 26, 2012
Time is another consideration. Successful aquariums require time for regular maintenance and care, and they are meant to be looked at and enjoyed, so you may not get as much out of the investment if you travel a lot or are constantly on the go. While marine fish can be lower maintenance than other pets, they will still need to be fed and the water quality will need to be monitored with routine water changes performed when necessary.
Your budget should also play a big role in the decision. How much do you want to spend and how much can you afford to spend? An aquarium and all the equipment to go along with it can be a big financial investment. Once you’re set up is up and running you also have to consider the cost of the inhabitants, food and other supplies that will be needed over time such as new light bulbs for the hood, new filter media and cartridges, water treatments/supplements that you may need for the livestock you keep. It’s a good idea to calculate these costs ahead of time so you have an idea what you might spend, say for the first year, just on the basics.
Once you’ve considered all of these things and you’re ready to purchase your tank, it’s time to research what fish or inverts you want to put into it, their behaviors, and their requirements in a tank. Visit local fish stores or browse online suppliers to see what’s available and what they require as far as space and care. You may be drawn to saltwater fish or African Cichlids, but is your tank big enough to support the fish you like once they reach mature size? Will territorial fish have the space they need? You may want a colorful reef, but can you afford the lighting, salt, live rock and other supplies necessary to support the corals you adore? Before you make the final decision on your investment be sure you’re prepared to provide an ideal environment for the fish you love.
The type of marine fish you choose may be influenced by your personality. Casual keepers may choose goldfish or assorted tropicals like tetras, barbs and rainbows to form an active, colorful community. More dedicated individuals may choose to keep uncommon species or those known for unique behaviors to observe and breed or a complex reef teeming with fish and invertebrates. Once you dive into the aquarium hobby there are so many paths to take! Talk to other hobbyists so you know what you’ll need and what you can expect, you may find eventually find yourself with multiple aquariums, like may hobbyists do.