Archive for July, 2008
Using Ozone in the Home Aquarium
Jul 31st
The use of ozone has long been a standard practice in industrial and public water purification plants, and large scale public aquarium filtration, as one of the best and most efficient means to increase water quality, while still being able to promote water conservation. One of the biggest problems to overcome in these closed water systems is the accumulation of dissolved organic waste from various biological sources such as animal waste and decomposing food and plant material.
In aquariums of any scale, mechanical filtration will remove large organic and inorganic solids, and biological filters will remove dissolved organic material in the form of Ammonia and Nitrite, this still leaves behind a large number of other dissolved and colloidal organic materials that will accumulate over time (the ones causing colors and odors being most noticeable). In most cases these materials are only removed by physical water changes, or chemical absorption media. While frequent water changes may be practical for removing these dissolved materials in smaller aquariums where you are not dealing with large volumes of water, it is not a practical method for removal of these materials in large systems or in systems where water conservation is at a premium. Using chemical absorption media is expensive, and is limited in is ability to remove all of these undesirable dissolved organics. This is where the use of Ozone comes in, I will try to answer some basic questions about ozone below
So, what is ozone, and how does it work to remove these dissolved organic molecules?
Ozone is a naturally occurring highly reactive form of oxygen gas comprised of three oxygen molecules (O3) that is also highly unstable and short lived. It is this inherent instability of the ozone molecule that is taken advantage of for use as a strong oxidizing agent. “Normal” oxygen, as found in air and water, has two oxygen molecules (O2) and is very stable. When ozone molecules break down, they lose an oxygen molecule, forming a stable “normal” oxygen molecule, and a free single oxygen atom. It is this free oxygen atom that attaches to dissolved organic compounds, which in turn causes them to break down into simpler forms that can consumed by heterotrophic bacteria , or recombine into forms that can be removed with mechanical filtration or protein skimming. The organic molecule that gained the free oxygen atom and subsequently broke apart is now said to be oxidized. This is a bit of an oversimplification of the process, but it is a about as general an explanation as I can give without losing too many of you. (and myself, chemistry was never my strong point)
How do I get ozone, and how do I use it in my aquarium?
As I have already discussed ozone is a highly unstable gas, so it is not possible to store, or purchase ozone, it only has a life span of a few seconds before it breaks apart. Ozone needs to be generated as needed with a device called an ozonizer or ozone generator. Most modern units available for the aquarium hobby use a Corona Discharge method to create ozone. In a Corona Discharge unit, air is passed through a strong electrical field which causes atmospheric oxygen (O2) to break apart into single oxygen molecules. Some of these oxygen molecules will then combine back together after passing through the electrical field to form Ozone (O3). This generated ozone gas must then be quickly used before it breaks apart again. Most marine aquarium hobbyists already have the perfect piece of equipment for introducing ozone into their aquariums, their protein skimmer. Ozone needs to have contact time with the water so that it is exposed to the materials that you wish to oxidize. Fractionating the ozone gas by drawing it into the air intake of your protein skimmer, you can use your skimmer as a highly efficient contact chamber. This works for both venturi type, and air pump driven protein skimmers. You need to make sure that your skimmer is made of ozone safe materials, and that you use ozone safe air tubing. Some plastics and rubber can be damaged by ozone, and cause leaks or failures if exposed for prolonged periods of time. There are also ozone reactors available, but they are a bit more difficult to use, and harder to find.
How much ozone needs to be used, and is it safe for aquarium inhabitants.
The best way to monitor and control ozone is with the use of an ORP monitor or controller. ORP stands for Oxidation Reduction Potential, and In terms of your aquarium water, it reads an electrical voltage in Milli Volts (mV) which measures the oxidation ability of the water. As Ozone is applied the ORP level increases. Natural sea water has an ORP value of 350-400 mV. ORP levels of 200 or less in your aquarium are indicative of low oxygen, high dissolved organic, conditions. By monitoring the ORP level in your aquarium, and maintaining it between 250-350mV, you can adjust your ozone dosage accordingly. Using an ORP controller simplifies this process to shut off you ozone generated at a desired ORP level. You should never exceed an ORP of 400mV in your aquarium. Ozone units like the Red Sea AquaZone Plus have a built in ORP controller.
Most manufacturers of ozone units recommend a dosage rate between 5-15mg per hour per 100 liters (26 gallons) many different size units are available, so you can choose an appropriate output unit for your size aquarium, and most have a variable output. Controlling your ozone output is very important, too much is not a good thing; very low doses will provide you with excellent results in most cases, overdosing can be harmful to both you and your aquarium inhabitants. There are several methods to make sure that you are applying the correct amounts of ozone into your aquarium. The goal when introducing ozone into your protein skimmer is for all of the ozone to break down in the chamber or escape through the top of the skimmer. You do not want ozone to escape freely into your aquarium, it will also oxidize organic material in there, which will cause damage to fishes gills, and invertebrate tissue. You also do not want high concentrations of ozone to escape into the air; it is harmfull to your lungs if in high enough levels. Most hobbyist units do not produce dangerous levels of ozone. You can use carbon in your sump chamber that the skimmer discharges into, or on top of your protein skimmer to absorb residual Ozone, and use an Ozone test kit to make sure that none is escaping the reaction chamber into your aquarium. Overdosing Ozone can also produce some harmful compounds, mainly in the form of hypochloric and hypobromic acids, this is why you should not exceed and ORP of 400 mV It is a not a good idea to use ozone in small confined spaces, a well ventilated room or aquarium cabinet should be considered. If you are not using an ORP meter or controller, a conservative approach should be used, stick to the 5mg per hour, per 100 liter rate to be safe. Another caution when using ozone is to use an air dryer to make sure that the air that is drawn into the ozone generator is dry, a simple and effective unit like the Red Sea Air Dryer, uses regenerable desiccant beads to draw moisture out of the air. Moisture can react with Ozone to create nitric acid, which can damage equipment, and lower the pH in your aquarium.
What are the benefits of using ozone?
Water clarity is the number one reason most people use ozone. There are many dissolved organics that can discolor your water, ozone will oxidize these and produce water that is crystal clear. This is especially beneficial to reef aquariums where light penetration is crucial. Many people do not even realize how discolored their water is until they see the difference ozone can make. Ozone also has disinfecting properties, pathogenic bacteria, single cell parasites and algae, viruses are all destroyed by contact with ozone. Increased dissolved oxygen levels from the reduced organic load and bacterial oxygen consumption. Ozone will destroy pesticides, detergents, and many other toxins that may be in your tap water. Many organisms release substances that are intended to defend themselves, or inhibit predators or competitors that can accumulate over time and become problematic will be destroyed by ozone. Ammonia and Nitrite are oxidized into less harmful Nitrate when exposed to Ozone. And as mentioned previously, using ozone can reduce the amount of water that needs to be changed in closed systems.
I hope that this has shed some light on Ozone use in the home aquarium, and that I answered some of the questions that you may have about Ozone use. Feel free to leave comments if you’re looking for any additional info.
Until next time,
Dave
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Loading ...Freshwater Clams for the Ornamental Aquarium
Jul 29th
Welcome back Patty Little to That Fish Blog!
Clams and other bivalves are well known for their filtering capabilities, absorbing toxins and nutrients from natural waterways both freshwater and saltwater. While clams and their relatives are common to reef aquaria, there are also clams available for freshwater tanks. The clams offered most commonly by pet stores are Corbicual sp. from freshwater Asian waterways. They can be interesting and beneficial additions to freshwater tanks, so I thought it might be worth a little article to help anyone along that may be considering the addition of these inverts.
These clams grow to about two inches across, and may live for months or years depending on their living conditions. They range in color from golden tan to black, and sometimes accumulate algae on their shells. They can be housed in even small tanks, 5-10 gallons, as long as they have enough water movement, decent filtration, and are provided with supplemental food when necessary. These clams should thrive in temps from 65-82 F and will need somewhat harder water to maintain a healthy shell. They are also best suited to an aquarium with a fine substrate bed as they like to burrow into the sand. You will be able to see the clam’s siphon as it protrudes.
Clams feed by filtering detritus and nutrients from the water column. Depending on your tank, you may or may not need to supplement your clam with invertebrate foods, as in many cases they will take in what they need when you feed your fish and as they stir through the substrate. The result should be a cleaner and clearer aquarium.
Now for some cautionary notes. First, be sure that you house your clam with appropriate tank mates. Avoid housing them with predatory fish and other carnivores like many cichlids, puffers, rays, and bottom dwelling shrimp and crayfish that may agitate the clam. Though they are buried, their tissues are delicate and can be easily damaged, and if they are frightened or disturbed, they will not be able to feed and may starve. Remove your clams if you must treat your aquarium for any reason, particularly with copper based medications, as they cannot tolerate any copper in the water.
Though you may find freshwater clams and mussels in local ponds, streams, rivers, and lakes, it is generally a bad idea to collect species from the wild for use in a home aquarium. Wild specimens may be carriers of disease and tiny parasites that can be detrimental to captive fish. As they absorb toxins, these toxins may also be released into the otherwise pristine water you maintain. The other issue is that some bivalve species reproduce by releasing tiny larvae. These larvae may attach to the slime coat or gill filaments of your fish, and the resulting infection may be deadly. It is best to purchase clams from a reputable dealer so you know what you are introducing.
Finally, though it should be common sense, as responsible aquarists or keepers of any non-native species, clams and aquarium water should never be disposed of or introduced to waterways for any reason. Introduction of non-native species can have horrific results. Use caution and be responsible with any plant or animal you may not be able to care for by contacting other enthusiasts, pet stores, or authorities for safe solutions to finding a new home to prevent serious environmental impact.
Thanks Patty,
Until Next Time,
Dave
(+1 rating, 1 votes) Loading ...Bugs in My Aquarium? An Overview of Amphipods and Copepods
Jul 25th
Please welcome back Desiree Leonard to That Fish Blog.
We as biologists at times take our knowledge for granted and forget that not everyone that is involved in the hobby is fully aware of all of the natural processes and progressions which occur in a saltwater aquarium.
Frequently we are contacted by frantic new aquarists with the following: “I have little bug – like things crawling all over the rock in my saltwater tank. I swear they weren’t there before. What are they and where did they come from? Are they going to make my fish sick? How do I get rid of them?”
Well, after talking the caller down off the ledge (so to speak), I give this answer:
In all likelihood, these are Amphipod
s and Copepods; shrimp-like crustaceans that dwell in the substrate and rocks. Because of the thousands of species contained within these groups in Class Crustacea, I am not going into detail about the taxonomy of these organisms, but here are some basic facts about these tiny crustaceans.
• There are both pelagic (free swimming), and benthic (bottom dwelling) bugs.
• Copepods occur in all types of aquatic ecosystems; freshwater, estuarine (brackish) and marine.
• Amphipods are mostly found in marine ecosystems, but there are some freshwater and terrestrial species.
• They are just a few of the tiny animal organisms that make up zooplankton, which contributes to the overall make up of plankton.
• These creatures eat phytoplankton (tiny plants and algae that also help ma
ke up plankton), small microzooplankton (the division of zooplankton that are smaller than 200 microns, or 1/127th of an inch in size), and detritus.
• Only a few of the thousands of species of copepods and amphipods known are carnivorous or parasitic, and these are rarely found in a saltwater aquarium system.
• For many saltwater fish and other marine species, copepods and amphipods are a primary food source, both in nature and in captivity.
• Because these tiny organisms are a natural part of the plankton food chain in the ocean realm, they are naturally going to occur in a saltwater aquarium environment. They are also micro-cultured as food for various species of adult marine animals, as well as used and tested as a food source in the research of culturing and rearing all kinds of tank-raised fry.
• Copepods and amphipods most often appear in closed aquarium systems after live sand and/or rock has been added. They will “bloom” in the tank when the temperature is slightly warmer and a food source is available.
Another critter that may be seen is the isopod. Also called pill bugs, fish lice and rolly-pollies, these animals are found in all parts of the marine environment. Most isopods are free living and harmless, feeding on detritus and algaes, however, some are predatory, or parasitic, and dangerous to other reef aquarium animals.
How did these “pods” get into the tank? Well, they’ve most likely been there for a while, just not in numbers large enough to notice. These organisms are microscopic or plankton sized when they start out, so until they grow large enough to be seen with the naked eye, you don’t know they are there. They hitchhike in on live rock and sand, and it is only after you have placed it into your aquarium that these organisms crawl out and make themselves at home.
If you have a large population of “pods” naturally, count yourself among the lucky few. Many aquarists go to great lengths to create a large healthy population in either their tank or refugium. Remember, these “bugs” are a natural part of a healthy aquarium ecosystem, as well as an important food source required by some species to survive. In most cases they won’t hurt anything. You shouldn’t have to do anything about them. If you are concerned however, you can provide a natural predator which should keep the population under control. Here is a list of species which pick at live rock, or sift substrate in search of these tasty morsels. Keep in mind those fish marked with a * are species which feed on these bugs as their primary food source. They are challenging to keep, requiring a well established aquarium with a consistently high “pod” population to live on lest they starve. Keeping more than one of these obligate “pod” eaters in a tank will most likely lead to a depleted food source.
• *Mandarinfishes/Dragonets; Synchiropus splendidus Blue/Psychadelic Mandarin, Synchiropus picturatus Green/Spotted Mandarin, Synchiropus stellatus Red Scooter/Starry Dragonet
• *Sand sifting gobies; Valenciennea spp. Sleeper Gobies, Signigobius biocellatus Twinspot/Signal Goby
• Most Firefishes are planktivores which may occasionally pick these bugs from the rock.
• Most Angel, Butterfly, Hawk, and Wrasse species spend their days grazing on fauna found on the rocks, however, do not consider this as a primary food source – merely an opportunistic treat.
• Seahorses feed primarily on these “pods” but are not a beginner fish and should not be housed with other fish.
Amphipods, copepods, and isopods are just a few of the fun little hitch-hikers we get questioned about, and we enjoy helping our customers with identification issues. If you should have other fun things pop up in your ecosystem, here are some other things you can do to help identify them:
• Buy some good invertebrate identification books for your saltwater reference library.
• Refer to marine invertebrate database and profile information, as well as photo galleries.
• If you have a personal saltwater Web site, create something like a “Can You Help Identify This?” page. You can display photos here and allow visitors to email back to you about them.
• Post a message in various aquarist forums asking for help with identification. If possible include a photo of good clarity, or provide a link to a Web page you may have created as described above.
*Photo Emailing Tip: When you email a photo to another aquarist asking for help with identification on something, be kind. Only send an image that is reasonably sized, and is clear enough to tell what you want identified including a “brief” description.
Thanks,
Until Next Blog,
Desiree
(+1 rating, 1 votes) Loading ...The Nitrogen Cycle and Conditioning Period in New Aquariums
Jul 24th
Introduction
A thorough understanding of how water quality affects animal life is essential if one is to be a successful aquarist. This is sometimes a bit difficult for beginners to accept, but please remember that it is a serious mistake to spend time learning about the habits and dietary needs of aquatic creatures while ignoring the “less glamorous” aspects of the hobby. Once you understand water chemistry basics, your appreciation of how fishes and invertebrates survive in their environments will be heightened.
The Nitrogen Cycle
The nitrogen cycle is a critical factor in the establishment of a crystal clear, well-balanced aquarium. Poor functioning of the nitrogen cycle is undoubtedly the most common reason behind new aquarium failures.
Basically, the nitrogen cycle is a process by which nitrogen is converted to other organic compounds that are then utilized by plants and animals as food. Nitrogen enters the aquarium via dead animals and plants, uneaten food, and the waste products of fish and invertebrates. The most toxic nitrogenous compound that is added to aquariums in this manner is ammonia. Ammonia occurs in two forms, ionized and un-ionized, with the un-ionized type being extremely toxic to aquatic organisms. The proportion of the total ammonia that is un-ionized rises as the water’s temperature and alkalinity increases.
Bacteria and the Nitrogen Cycle
Two types of bacteria control the functioning of the nitrogen cycle. These bacteria are aerobic, which means that they require oxygen in order to survive. Bacteria populations develop and thrive on substrates that are exposed to oxygenated water, such as gravel and the filter pads and carbon within filters.
The process by which aerobic bacteria convert ammonia to less harmful compounds occurs in two phases. Nitrosomas bacteria convert ammonia to compounds known as nitrites. Nitrites, while dangerous to aquatic organisms, are less toxic than is ammonia. In the second stage of the process, bacteria of the genus Nitrobacter utilize these nitrites as food, and in doing so convert the nitrites to nitrates. Nitrates are the end product of the nitrogen cycle, and are the least toxic of the compounds involved.
Nitrogenous bacteria (the name given to the various species of bacteria that feed upon ammonia-based compounds) exist in huge populations in natural water bodies and in healthy aquariums. Until such are established in your aquarium, its levels of nitrogen-based compounds will be toxic to nearly all fishes and invertebrates.
The time it takes for healthy populations of nitrogenous bacteria to become established in an aquarium is often referred to as the “conditioning period”. Its actual timetable varies greatly depending upon the unique characteristics of each aquarium and of the animals therein, but usually falls in the range of 1-6 weeks.
Please bear in mind that water clarity is not an indicator of the functioning of the nitrogen cycle. The only sure way to monitor the cycle is via frequent testing of the water to determine the levels of ammonia, nitrates, and nitrites (please see below).
Altering the Nitrogen Cycle
Your aquarium’s conditioning period may be shortened by the addition live aerobic bacteria. I have had good experience with Biozyme Freshwater and Biozyme Saltwater, and strongly urge you to use either with all new aquariums. Products such as Coral Vital LSB Pro, which accelerates the growth and reproduction of bacteria in marine aquariums, should also be considered.
You can also help the process along by adding filter material from a well- conditioned, parasite-free tank into the filter of your new aquarium. Natural materials such as “live rock” and “live sand” also host beneficial bacteria and offer another option.
In the past, it was standard practice to use hardy fish, such as domino damselfish in marine aquariums or guppies in freshwater aquariums, to hasten the conditioning period (their waste products started the process and provided food for bacteria). However, additives such as those mentioned above are more effective and infinitely kinder, as many of the fish subjected to this process did not survive.
When cleaning your filters, always retain a bit of old filter medium (carbon, floss) and add this to the clean filtering material. In this way, you will introduce aerobic bacteria into the newly-cleaned filter. These will reproduce rapidly and greatly increase filtration effectiveness.
Please be aware that the addition of packaged bacteria does not eliminate the need for a proper conditioning period. Water quality must still be monitored carefully, and animals should be introduced to the aquarium in small numbers.
Measuring the Levels of Nitrogenous Compounds
The frequent use of test kits is essential during the aquarium’s conditioning period, and on a regular basis thereafter.
Ammonia should be tested daily until you notice a sudden decrease in its level. This decrease signals the presence of Nitrosomas bacteria. Nitrate levels will then follow the same pattern, as the Nitrobacter bacteria become established.
The conditioning period may be considered at an end once the nitrate levels drop substantially. You may now begin to introduce fish and invertebrates into their new home. Be sure to add animals in small quantities, so as not to overwhelm the nitrifying potential of the bacteria present, and observe them carefully for signs of stress.
The pH level should be checked often as well, since the water may become acidic during the conditioning period.
I am very interested to hear about your successes and challenges in establishing new aquariums, and will be sure to pass along your information to my readers in future articles. Thanks, until next time, Frank.
An interesting technical article on the role of nitrogenous bacteria in natural marine habitats is posted at:
(No Ratings Yet) Loading ...Global Warming, is it really to blame?
Jul 22nd
Please welcome Cory Shank to That Fish Blog. Cory is an on-staff marine biologist here and our resident “Coral Guy.” Take a look below to read his thoughts on the future of wild coral. 
Corals reefs are enjoyed by millions of people each year, while on vacation or in the comforts of their own homes. Coral reefs are the most biodiverse ecosystems in the ocean and arguably in the world. It is well known that coral reefs are beginning to decline world-wide, from Australia to the Florida coastline. This is a major concern for industries economically involved, the aquarium trade, global tourism, and commercial food fisherman. The problem is, how do we stop this disturbing decline when we don’t know enough about the issues causing it?
The hype over global warming has many believing that the water temperature increases are causing the coral degradation. Water temperature plays a major role in maintaining the health of a coral reef ecosystem. In our aquariums, we use fans and chillers to keep our tanks at a desirable temperature, but reefs depend on natural currents and climatic conditions. In the past, the world climate has warmed much faster and more dramatically and the corals have lived on. The El Nino event of 1997-98 caused massive coral bleaching throughout the world’s coral reefs. Ten years later, many of these areas have recovered and are showing signs of expansion. So it is reasonable to believe that this cannot be the only reason behind the coral destruction.
So, what else can be going on? I was in Hawaii recently and spent most of my time in the water observing the wonderful fish, corals, and invertebrates. I noticed quite a bit of new coral growth and plenty of fish. However, there were areas that were not doing so well. Along the main highway, just off shore, were large coral colonies covered in filamentous algae and diatoms, not at all what the reefs looked like 5-10 miles offshore
. There the corals were thriving, and no algae could be seen. Along the shoreline, there are drainage pipes coming from the roadways and further up the mountains. This is where all of the runoff ends up. With more development come more impervious surfaces, chemicals, soil, and debris that enter the oceans, increasing the amount of siltation that occurs from the breakdown of coastal buffer zones. The soil and debris enter the ocean, choking out the coral. This also adds nutrients to the water, leading to enhanced algae growth, which also chokes out the coral. Coastal development is occurring all over the tropics, and new resorts and hotels and homes are being built every year, increasing to the problem.
With the increasing amount of hotels and resorts near where the coral reefs are located, tourism poses a new wave of problematic issues. There are snorkelers and divers who may not respect the reefs and act irresponsibly, stepping on the corals, catching the fish, and polluting the waters. While in Hawaii and the Florida Keys on separate trips, I have witnessed people standing on corals with their snorkel fins not considering the damage they may be causing. The amount of trash floating around, stuck in between corals, or just buried in the sand is appalling and virtually unavoidable these days.
If Global Warming is occurring, causing the sea surface temperatures to rise, then everyone needs to step up and start protecting the reefs in any way that we can. At the current rate of degradation, a large percentage of coral reefs may disappear in the next 10 to 20 years. This will have devastating economic impact on the locals populations and to everyone else in the world that relies on income from those areas around the world. Skyrocketing prices on everything from ornamental aquarium specimens to the shrimp for your picnic or barbecue will be the likely result, as these things become harder to come by. It is going to take a worldwide effort to help save the coral reefs, and we are running out of time, so please do your part and help protect our most biodiverse ecosystem.
Thanks for the great article Cory. Please write in with your thoughts or observations on this important topic.
Until next blog,
Dave
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