Tank disasters cause people to leave the marine aquarium hobby more than any other reason. All of the following, emotionally draining and expensive disasters have actually happened to aquarium tank owners. Some disasters destroyed not only the tanks but aquarist homes as well. Read carefully and learn from someone else’s mistake instead of your own. One disaster can wipe it all out. Read on. Moving Too Fast Although in and of itself this may not cause a disaster, it is the root cause of many of the following disaster scenarios. Patience is the absolute number one rule in this hobby. Prevention: Take the time to educate yourself on all aspects of your tank. Plan as much of your tank setup as possible. Make absolutely sure you are buying the equipment, fish and other livestock that is right for your tank. Confer with fellow aquarists before moving forward. Not Understanding Tank Cycling Tank cycling, also referred to as the nitrogen cyle or new tank syndrome All aquarists must understand what tank cycling is or risk a mass die off. A tank cycle is necessary to establish beneficial bacteria that will eat toxic ammonia, nitrites and nitrates, but a cycle can also kill livestock. One needs to also understand the various reasons why more tank cycles can happen long after the tank has been established. Prevention: Do not add livestock during a cycle. Do not add too much livestock at one time as it will cause a new cycle. Remove dead fish quickly! Understand why tanks can cycle more than once. Read up on tank cycles! Learn the causes of ‘mini-cycles’. Excellent article: What is the Nitrogen Cycling Process? Pump Gets Blocked Flow is perhaps the most important tank parameter. If the intake to a pump, sump, refugium or other system becomes blocked, flow may be interrupted. Without flow, water quality will degrade quickly and temperature may drop suddenly. With this type of disaster, some aquarists have lost most of their tank livestock overnight. Cucumbers, anemones and other creatures can block intakes. Filters can become saturated with detritus, seaweed (macro-algae) or detritus and cause blockage in the filtration system. Pumps may burn out if they are blocked or if they run dry. Prevention: Examine your filtration system and sequentially list each and every item that water flows through. Determine if anything can become clogged and clean it on a regular basis. Consider pushing a bulbous shaped piece of screen into an intake. Most pumps come with a small vent-like attachment that goes over the intake and prevents blockage. Disassemble and clean pumps often. Soak them in vinegar to release salt build up in them. (Rinse out all vinegar). Replace pumps and pump impellers before they break. Keep spare pumps or pump impellers on hand. Floods and Spills Water on the floor is caused by pumps or attached hoses that get out of control. Floods can also be caused by poorly designed plumbing usually between the main tank and a sump or refugium. Almost every tank owner has let their change out container overflow when filling it with filtered water. Prevention: Use plumbing designs that cannot flood even if a pump fails. For instance, pump water from the top of the main display upward towards the sump and let gravity bring water back through a pipe near the top of the sump. The return pipe should be several times larger than the uptake and very difficult to block or clog. Flexible, curved tubes are less likely to clog than PVC pipe with 90 degree turns. When filling large containers with filtered water use loud, audible timers to remind you when they are full. A wrist watch with a countdown timer is ideal. Failure to Properly Clean Filter Media This applies especially to bioballs but also to mechanical filtration and large carbon packs. If bioballs are filled with beneficial bacteria and you clean them with bacteria-killing tap water, then a sudden ammonia spike could result. The sudden lack of ammonia eating bacteria will cause an ammonia spike that can quickly kill everything in a tank. Also, if you have lots of bioballs and you remove them all from the tank at once, an ammonia spike could result. Prevention: Clean bioballs and other filtration media with a soap-free brush in used tank water from a water change. Remove bioballs gradually, perhaps 25% at a time. Electrical Disaster There are a substantial number of aquarists who have failed to read equipment safety instructions and had electrical disasters some of which resulted in their homes catching fire. Unventilated chillers or equipment, failure to use drip loops, faulty wiring, lack of GFCI outlets and other electrical problems have all resulted in serious problems that can destroy a tank and your home. Prevention: Use drip loops! Allow power cords and any cable to hang down in a loop so that when water spills it doesn’t run along the cable down to the equipment. Please don’t say ‘water spills won’t happen to me.’ Aquarium equipment can produce a lot of heat therefore make sure that all electrical equipment has adequate ventilation. One tank owner put a chiller in a closed cabinet. Because there was inadequate heat dissipation the chiller overheated and caused a major house fire. Ground all electrical devices. Old and faulty equipment often lets electrical current leak into the water. Consider putting a titanium ground in your tank water to prevent stray voltage from killing you and your fish. After a water change out, use a flashlight to check for water spills before restoring power. Putting Contaminates in the Tank Several common scenarios: You wash your hands with soap and don’t quite rinse all the soap off, then you put them in the tank. Soap may have phosphates. Your maid or a well meaning friend sprays Windex all over the tank glass to clean it. Windex has a lot of ammonia and thus will cause a cycle. This scenario has caused many fish kills! You put your hands in the tank after you touched some other contaminant such as lotion or your dog’s anti-flea and tick medication. You worked on your lawn mower engine then put your hands in your tank –bad idea. Windex contains Ammonia! Understand that it only takes a few parts per million of a contaminant to kill everything in your tank. Benzene is found in plastics, rubber, resins and synthetic fabrics like nylon and polyester, and in solvents used for printing, paints, and dry cleaning. Benzene is also found in gasoline. Benzene is considered dangerous to humans if it exceeds 5 parts per billion in drinking water. ‘Dangerous’ in this case means immediate damage to the central nervous system as opposed to the long term effects which may include cancer. Prevention: Consider using lids on tanks to prevent airborne contaminants from entering the tank. You can cut a lid using Plexiglas or have a glass one custom made. If you make a custom lid, ensure the tank itself is ventilated so that oxygen exchange with the water can take place. Educate everyone, including maids and children, about the importance of not touching your tank. Rinse all soap off your hands by rubbing them vigorously under running water. When cleaning the outside of the tank glass, spray the window cleaner on the rag while standing at least ten feet away from the tank. Use of high grade carbon is an excellent way to eliminate contaminants from the water. Polyfilter can remove copper. Water changes can also remove contaminants. Tell children your tank is not a wishing well so they won’t throw a penny in for luck. Pennies are made of copper and will kill every invertebrate in your tank. Inadequate Flow and Poor Aquascaping Cause Detritus Traps If there is improper or inadequate flow, especially under the rock, an abundance of detritus may settle in these pockets causing nitrates and phosphates to rise high enough to start killing livestock. Detritus may also accumulate in filters (including filter media), bioballs, tubes or anywhere there is inadequate flow. Prevention: Ideally all water should go through the filtration system on a regular basis. There should be no static water anywhere in the tank. Aquascape your tank so that water can enter the caves and holes in the rock and leave through a different opening. Avoid pockets in the rock that have an opening but no exit. You can use small lengths of PVC pipe to prop up the rock and get more flow under it. If you do this, drill holes in the pipe for flow and so that inverts don’t get trapped in the pipe. Ensure rock is stable. Match pump capacity to the size of your tank. Ask fellow aquarists what pumps they use. Too much flow can stir up sand and cloud the water or cause fish to become stressed. Sand Becomes a Detritus Trap Detritus can settle into the sand bed and build up over time to dangerous levels. One aquarist, drained his tank to remove a fish. When he pumped the water back in, it stirred the bottom up and released a huge amount of detritus that had settled in the sand. This resulted in an ammonia spike that killed everything in the tank. In the worst case scenario, a deep sand bed (DSB) never gets stirred and toxic deposits of hydrogen sulfide build up. When released these deposits kill everything very quickly. Prevention: Get sand stirrers such as Nassarius snails, conchs, sand-sifting starfish or gobies that will stir the sand on a daily basis. Ensure there is good flow in the tank so that detritus will get removed by the filtration system before it has a chance to settle on the sand. Some people, manually deep stir the sand in very small sections every few days so as not to release too much detritus in one day. (Warning: If your sand bed is already full of toxins such as hydrogen sulfide, stirring even a small amount of sand could release those toxins and cause a die off.) If you use DSBs, put them in a refugium and use floss or other media to filter out the detritus before it enters the DSB chamber Major Disease Outbreak and Bad Medicine Notice white spots Disease outbreaks do not necessarily kill all fish in the tank because some fish may be more resistant to Ich than others. On the other hand, a total loss of all fish to disease is not uncommon. Marine Velvet is quite deadly. By the time this disease is diagnosed, it is usually too late to do anything about it. Disease can enter the tank in many ways and there is substantial debate on this subject. (This description is not by any means meant to be a complete discussion of marine fish disease causes and treatments.) Some common ways Ich can enter your tank: Introducing a diseased fish into the tank Letting the slightest drop of tank water from the fish store or any infected tank spill into your tank. Live foods, such as brine shrimp, may come with Ich in the water. Frozen foods may contain the Ich in its tomite or ‘free-swimming’ stage. When thawed they can reanimate. The ability of small crustaceans and parasites to reanimate is not at all uncommon. Freezing fish or fish food at minus 6 degrees Fahrenheit for 72 hours will kill parasites. Prevention: Quarantine all new livestock for six weeks in a special quarantine tank. Copper can be dosed in a quarantine tank if the fish looks sick. Hypo-salinity is also effective for fish. Do not treat invertebrates with copper or hypo-salinity. Many aquarists have put copper in their main tank and then watched all of their invertebrates die. Improper use of medications is not an uncommon cause of tank crashes. Gamma irradiated frozen fish food will be ich free. Frozen blood worms are also free of marine ich. Consider carefully anything else that is introduced into your tank. Major Pest Infestations Asterina Starfish, Flatworms and Aiptasia Marine pests are numerous and some can cause a tank disaster. Coral eating nudibranches can wipe out corals very quickly. Mantis shrimp may eat small fish. Live rock often contains many interesting and beneficial hitchhikers but it can also import dangerous pests into a tank. The Asterina species with a bluish spot in the center will eat coralline algae. Other types of Asterina are generally harmless. Acropora Red Bugs will kill expensive acropora corals. Flatworms and aptasia can also slowly kill many livestock. Some pest treatments, such as flatworm killers, will kill many flatworms thus causing a die off and ammonia spike. If the directions call for water changes after treatment then do them. Prevention: Quarantine of all livestock is the best way to prevent pests from entering a tank. For new tanks that have just been filled with live rock and have finished cycling, introduce livestock slowly into the tank, one fish at a time to see if they are susceptible to pests that arrived on your new live rock. Consider dipping corals to kill pests on them. Study potential pests ahead of time and be ready to react quickly if they appear. Pests, like blue spotted Asterina, can be eliminated by picking them out with tweezers before they become numerous. Predators of pests are usually not one hundred percent effective in a tank environment. Heaters Gone Wild Aquarium heaters generally do not have very sophisticated thermostats. On some heaters, the thermostat may malfunction causing the heater to cook the tank. Many tanks have had die-offs for this reason. There have also been cases where heaters with too low wattage were used and during the colder winter months the tanks got too cold causing a die off. Prevention: Choose quality heaters by getting good recommendations from experienced aquarists. Titanium heaters tend to be superior. Replace heaters at least every two years. Consider using 2 heaters in case one stops working. Heaters can be attached to more precise temperature controllers for greater safety. Chillers can also prevent malfunctioning heaters from cooking your tank. Choose heaters with adequate wattage. Five watts per gallon is plenty. Audible temperature alarms are relatively inexpensive. Glass Heater Breaks Glass heaters should never be removed from water when plugged in. Removing them for only a couple seconds can cause them to break and possibly electrocute you and everything in you tank. You may try this and notice that you can remove them without them breaking –this doesn’t mean they won’t break the next time you try it. This scenario has happened many times. Many heaters, contain a copper element which can fall into the water after the heater breaks. Copper will slowly kill off all inverts –small and large. Prevention: Use shatter-proof heaters. Unplug all heaters before removing them from water –even if removing them for only a second. Handle glass heaters with great care, especially during water changes. Put a titanium ground in the water. Power Outages A lack of power means no flow or heat. Without flow your tank livestock will die – possibly in a matter of hours. Prevention: Develop a plan to deal with power outages well in advance. If there is limited power during an outage, use it to drive the flow and heater only. With any of the following backup power options, the use of a good surge protector is strongly recommended. Options: Power generators can be very expensive but for large tanks they could prevent a loss greater than the cost of the generator. Battery Backup UPSs such as those used to power computers during outages may be able to run a pump and a heater for short period of time. Battery backup units with enough power to drive a pump and heater for several hours can be very expensive. Battery powered air pumps can provide some limited flow and can be ordered online. They are inexpensive. Auto power inverters can create 100 watts of AC power to keep a small pump and heater going. They are relatively inexpensive but consider the cost of gasoline with this option. Manual Flow can be created by scooping up water and pouring it down into the tank on a frequent basis so as to create surface agitation. Heat packs may help. Friendly Neighbors with extension cords can help if only your home is without power. Auto Power Inverter Massive Overfeeding If a very large amount of food is dumped into a tank, usually by a well meaning child, and goes unnoticed, it will decay and cause nitrates and phosphates to rise high enough to start killing first the corals, then other invertebrates and if it goes high enough –your fish too. Your fish and corals can die in only hours in this scenario. Prevention: Keep tight lids on tanks. Educate family and friends on why they must not touch the tank. Tell children that small sharks are hiding in the rocks. Anemone Nukage When an anemone dies and decays, millions of nematocysts float all over the tank and eventually kill everything. If an anemone crawls into a pump or Koralia and gets pureed, minced, diced or chopped up, the nematocysts will go everywhere and kill everything very quickly. This is anemone nukage. The anemone’s nematocysts contain a potent paralytic neurotoxin. Anemone Prevention: Anemones are for advanced aquarists who have adequate light, excellent water quality and an understanding of how to deal with anemones when they become a problem. Ensure pumps cannot be blocked by any livestock. Dropping Electrical Equipment into the Water Don’t laugh, everyone can make mistakes. Prevention: Unplug all equipment during water changes and maintenance. After water changes and maintenance, use a flashlight to check for water spills on equipment before restoring power. Handle electrical cords with dry hands. Bad or No Top Offs When salt water evaporates, the salt does not evaporate with it. If you have ever seen a salt flat, it’s obvious to see. Some beginners have topped off with salt water causing salinity to rise and ended up killing everything in the tank. Failure to top off will also cause salinity to rise. Salt Flats - Lake Hart Prevention: When salt water evaporates, replace with fresh water. Use a marker on the glass (like a small piece of tape) to determine the proper water level when topping off. Use of an automatic top off (ATO) can greatly reduce the need for manual top offs. With an ATO one only needs to refill a fresh water reservoir on a far less frequent basis. Also, consider placing your tank in a cool spot in your home to reduce evaporation. Before doing any tank maintenance that might suddenly change the water level, unplug your ATO. An unintended ATO replenishment with fresh water could cause a drastic reduction in salinity killing everything. Unsuitable Livestock Choices One aquarist read somewhere that Dwarf Moray Eels are less aggressive than the larger types. His new Dwarf Moray eel started out by eating two fish that had cost him $260 each! This aquarist made the mistake of not reading enough about his choice. It is crucial that each livestock choice be studied and evaluated for your tank using criteria such as: Is your tank large enough? Fish tend to become more aggressive or stressed out in tanks that are too small for them. If the tank is undersized for the fish, the filtration may not be able to handle the fish’s waste. Compatibility with other livestock. Take note of how aggressive a fish is: peaceful, semi-aggressive, aggressive or predator? Semi-aggressive fish can kill! Does the creature have a favored prey or is it the natural prey of something already in your tank? Dottybacks and wrasses will probably eat your shrimp. Starfish may eat your clams. Some crabs will eat only starfish. Corals can kill each other. The blue-ringed octopus’ venom is deadly to humans. No anti-venom is currently available. Do not assume that because one fish is peaceful that a very similar fish will also be peaceful. Many corals, invertebrates and some fish require excellent water quality. Do you have sufficient light? Many corals and some invertebrates require advanced lighting such as metal halides. Moray Eel Prevention: Do not give in to “new fish emotion” which is very similar to “new car emotion”. Fish store sales persons, however nice, have misled aquarists many times so do your own research. After studying your potential choice you may decide not to buy it for very good reasons. You might take a good fish book to the store with you and look up the fish’s requirements while you are there. Use species compatibility charts. Sudden Algae Outbreaks Algae outbreaks can quickly overtake a tank, grow over and kill corals and other livestock. Algae needs three things to grow: light, nitrates and phosphates. If you see a sudden algae outbreak, one of these three things has changed. Reducing nitrates and phosphates is of one of the greatest challenges of marine aquarists. Prevention: Reduce nitrates and phosphates to zero! The methods for reducing these chemicals are numerous but the best ways are: Install good protein skimmers. Use refugiums with plenty of macro-algae and a very strong plant light. Regular water changes. Do not overstock. Know how many inches of fish your tank can handle. Use cycled live rock which is an excellent filter. Do not overfeed. Nitrate and phosphate reactors use chemical media to reduce these chemicals. Use reverse osmosis (RO) or de-ionized (DI) water only. Test your RO and DI water with a Total Dissolved Solids (TDS) meter because filters may become prematurely worn out and lose effectiveness. Use of tap water has caused many algae outbreaks. Tap water often has phosphates in it and charcoal filters will not remove phosphates. One person used a garden hose to fill his tank with tap water. The hose had copper fillings which are deadly to invertebrates. If an algae outbreak occurs but nitrates and phosphates are near zero, consider that these two algae nutrients may be settled in the rock and sand but not in the water. If so clean the rock and let snails, gobies or starfish sift the sand. The Great Tank Burst Poorly constructed homemade tanks or tanks not placed on a level surface, when filled with water, will put undue stress on the joints and seals causing a burst. Also, the seals in some very old tanks can weaken. More than one aquarist has had to deal with a hundred gallons of salt water in their living room. Consider that one gallon of water weighs 8.5 pounds (2.2 liters weigh 1 kilogram). Prevention: Buy from quality tank manufacturers! There are too many cheaply made tanks on the market. Test used tanks by filling them with tap water, drying the outside and let them sit for several days. If possible weigh all live rock, sand and equipment before putting it in the tank. Know the total weight and ensure your stand will support it. Do the math! Make sure your tank is level and sitting on a completely flat surface! Do not trust standard manufacturer stands in an earthquake zone. Thick steel stands or stacked cinder blocks will be quite sturdy. Attach a nice piece of panel or wood to the front and sides if the cinder block looks too unsightly. Avalanches Rock is often stacked in dangerous ways in a tank. What many aquarists don’t realize is that sand slowly dissolves causing even the most carefully stacked rock to come tumbling down and crack or bust the glass. Long before sand dissolves, livestock can burrow in the sand under the rock and cause an avalanche. Some livestock, such as octopuses, are very strong and can easily shift rock around causing an avalanche. True Tale of horror: One aquarist heard a loud crash followed by a wave of water as he lay in bed at 3am in the morning. A large rock had tumbled down and smashed through the front glass of the tank. The tank emptied in only a few seconds. The salt water hit electrical cords and surge protectors and destroyed his TV and other electrical appliances. His living room had substantial damage mostly to carpets and furniture. All this caused by 80 gallons of salt water. Prevention: Place rock gently on the bottom of the tank –then add sand. One fellow put the rock down too hard on the bottom glass of his tank and busted it –while it was full of water. Consider using aquarium safe concrete to cement most of the lower rock together. You may wish to leave some of the rock un-cemented until it has been aquascaped to your liking. Some aquarists drill holes through the rock and secure it together using strong rods or PVC pipe. Fast Stocking and Over Stocking Placing too much livestock in a tank all at once will cause a ‘mini-cycle’ that kills fish and invertebrates. When new fish are added, the beneficial bacteria must be given time to increase and deal with the added fish waste. Adding one fish will generally not cause a cycle but adding a dozen fish to a fifty gallon tank will cause a fish killing cycle. Also, adding more fish than your tank can handle will cause ammonia to spike and kill fish. Prevention: Determine how many inches of fish your tank can handle and add fish and other livestock gradually. Allow beneficial ammonia-eating bacteria time to adjust to the added fish waste. Bad Test, No Test Many problems that might snowball into major disasters can be prevented –if caught early. The most important tests are temperature, salinity, and Ph. If keeping invertebrates or expensive fish that require excellent water quality one must also test for alkalinity, nitrates, phosphates, calcium and magnesium. Keep in mind that for various reasons nitrates can spiral out of control in a day or two and start killing livestock. Old test kits can go bad and give bad results. Failure to test can also allow Ph to change drastically causing corals to begin dissolving because the water is too acidic Prevention: Test often. Check temperature every day. Use ammonia indicators to get a warning. If anything seems wrong in the tank, test water quality. The more stable water quality tends to be the less testing is needed. If water quality tends to be bad then test more often. If using instruments, ensure that they are calibrated. Paper strip tests are quick and easy. Bad Salt Seal salt containers tight. If moisture gets in the salt it can cause precipitation resulting in lower alkalinity and calcium. If salt has hardened into a large chunk, it is almost certainly in this condition. Although salt in this condition will still be usable, one must consider if anything else besides moisture was absorbed into the salt such as auto exhaust fumes from the garage. One person used 10 month old salt that had not been kept in a tight container. Two days later most of his livestock was dead. Use salt specifically formulated for marine aquariums Prevention: Seal salt containers tight! Do not buy a year’s supply of salt unless you are absolutely sure you can keep it moisture free. After mixing water let it circulate overnight. The water should be clear the next day. Shake salt containers if possible before each use. Rotting Fish & Toxic Slugs A large dead fish quickly becomes a nitrate factory. A large trigger fish or tang can be enough to push ammonia above a fish-killing threshold. Die-offs that occur for other reasons can also cause ammonia spikes. Some livestock such as Nudibranchs and Mandarin Dragonettes, when stressed, can release toxins into the water that kill fish and invertebrates. Prevention: Remove all dead fish quickly. Systems with excellent nitrate reduction may be able to handle the nitrates produced by a dead fish. If the fish cannot be removed, do water changes until nitrates and ammonia are low again. Determine whether livestock can release toxins before you decide to buy them. Oxygen Deprivation Good water quality requires good levels of oxygen. Some aquarists have used tight fitting lids on their tanks and cut off oxygen exchange with the water leading to a die-off. Prevention: Most oxygen exchange takes place on the water surface. Ensure good air flow over the water surface. Skimmers will help with oxygen exchange. Ensure that there is some vertical water movement in the tank. Do not use tight fitting lids on tanks. Attempting to Drill Tempered Glass In order to connect sumps or refugiums with the main display tank, drilling glass may be required. If the glass is tempered, it cannot be drilled –attempting to do so will cause the glass to shatter. More than one aquarists has ruined a large tank by trying to drill tempered glass. Prevention: Contact the tank manufacturer or look at the manual to determine if the glass is tempered. With some tanks, only the bottom and back panes may be tempered. Vacation Disasters Not being home when a disaster happens will compound the problem. Many of the aforementioned problems have happened when tank owners were gone. Prevention: Choose your home and tank sitter wisely. Try to find someone who has experience with aquariums. School teachers and technical professionals are usually pretty good. Use ATOs and make sure the fresh water reservoir is full. Know how much food auto-feeders will drop into your tank. Do major maintenance several days before leaving town. Test your system: give your tank at least several days to run unattended while you are still home. Macro-Algae Die-off If Chaetomorphia, Caulerpa or other macro-algae do not get sufficient light they will rot, turn white and die-off causing a potential ammonia or nitrates spike. Ensure that macro-algae gets strong florescent light with a spectrum of 2700K or higher. Also make sure the light is no more than a few inches from the macro-algae. Caulerpa can shoot out a mass of spores causing a die-off and subsequent ammonia or nitrate spike. This is why Chaetomorphia is in general a better choice. Prevent Disasters Prevent many disasters by developing a comprehensive maintenance list and schedule for your tank. Here are suggestions for a maintenance list: Refill ATO reservoir Replace filter floss Empty skimmer cup Scrape glass Clean glass cover on lighting fixtures Replace pump impellers Trim Chaetomorphia, cut out dead parts Clean Skimmer Check, change bulbs before they burn-out Add trace elements if necessary Dose for Ph, calcium and Alkalinity if necessary Clean outside of glass Clean filtration systems Replace old equipment Clean and check your pump Clean overflow teeth, grates and vents Clean powerheads. Clean air fans used to cool tanks Soak pumps in vinegar overnight to break up calcium deposits Check tank and equipment joints / connections for signs of leaks. Concluding Advice Carefully plan changes and additions of any kind to your tank and most importantly go slow! Many of the disasters listed in this article can be prevented by making changes to your tank only after you fully understand the underlying issues and consequences. Bad advice is easy to come by on the Internet, so get advice from a consensus of experienced aquarists.