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Reef Aquarium Stability Guide
Last updated on November 17th, 2023
Reef Aquarium Stability - The Key to a Successful Reef Aquarium
The key to a successful reef aquarium isn't a magical formula, special method, or even a certain level of alkalinity, but rather stable reef parameters. Though most of us hear this often, what does "stability" really mean? The term stability refers to keeping a value near consistent. Consistency is key to the reef aquarium as fish and coral are not adapted to deal with large changes.
With fish and coral being overly sensitive to change, the objective is to keep everything as stable as possible. How do we keep reef tanks stable though? In the ocean, the large water volume and turnover handles this by itself. Most of us in the hobby, however, have less than 100 gallons of water, others up to 500 gallons. Even if you were to have 1,000 gallons of water in your tank, this does not even begin to compare to the water volume of the ocean. Because of this, we need to put in a little extra care to maintain stability in reef aquariums.
The easiest option for aquarium stability is to use the Neptune Apex Aquarium Controller to measure and adapt any parameter that does not remain stable. With the availability of the Trident for the Apex, nearly everything can be handled by this controller and make everything much easier to maintain. The obvious part about the Apex is that with the added stability comes a cost. The Neptune Apex, Trident, measurement probes, and other controller plug-ins become very expensive, very quick. In fact, this cost quickly reach the thousands of US dollars and can get even more expensive as you build on to the controller. At the time of writing this article, I do not even own one because of this. So how do I maintain a stable reef aquarium? I measure and track my parameters.
Using reliable equipment, quality test kits such as the Hanna Checker, and tracking reef parameters at least weekly, leads to consistent, stable reef parameters over time. Though the control may not be as perfect as a Neptune Apex Aquarium Controller may provide, measuring parameters once or twice a week and tracking them is generally more than sufficient to achieve a successful, stable reef aquarium.
Which Reef Tank Parameters are Most Important for Stability?
There are a lot of parameters in the reef aquarium that can be measured, but not all of them move fast enough to worry about measuring more than once per week, some not even more than once per month, others not at all. There are a few very important parameters however that should remain stable at all times.
1) Aquarium Temperature Stability
As we all know, there is a range of acceptable temperatures that are considered acceptable in the reef tank, between 77 and 80 degrees Fahrenheit. Most hobbyists tend to assume that if their temperature is within this range, that the tank and it's inhabitants are okay. This is not necessarily the case. A sudden temperature change from 80 degrees to 77 is actually enough to stress sensitive corals, fish, invertebrates and other marine life. Any changes to the aquarium parameters need to be made gradually over time and you should keep reef aquariums' temperature level.
In that case, what does this range really mean? This range is where you should pick a temperature within and maintain your reef aquarium within 0.5 to 1.0 degree of the chosen temperature. This stability will help keep all tank inhabitants, even the more sensitive ones, happy and healthy.
Now that we know the importance of temperature stability in reef tanks, how do we maintain this temperature stability? There are a few ways to do this.
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Aquarium Temperature Controllers
Aquarium temperature controllers, also known as aquarium thermostats, are at the core of temperature stability in reef aquariums. Though many heaters have built-in thermometers or controllers, and some are "pre-set", they are not as accurate as using a temperature controller. I do not personally trust a hot glass or titanium tube to tell me the temperature of my tank.
Temperature controllers can be found at different price points and features including wifi connectivity and both heating and cooling control. These controllers will turn your heaters on or off based on finer temperature control than the heaters' built in control can achieve. If you use an external thermostat with heaters that have built-in thermostats, you can set the heaters themselves a couple degrees higher than the controller as a fail safe in case the controller were to fail on. This redundancy will add safety and security to your reef aquarium.
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Temperature Stability with Multiple Heaters
Like everything else in the hobby, having redundancy will always pay off! There is not a lot to add to this statement when it comes to heating your tank. Using multiple heaters will account for heating the water if one of the heaters fails and doesn't turn on. This will hold the tank over a little while you replace the failed heater. Additionally, placing the heaters in different locations within your sump can provide more consistent heating of the water. Redundancy in reef aquariums is critical for the "Life Support" equipment, such as heaters, return pumps, lighting, and wave makers.
Recommended Reef Aquarium Heaters:
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Heating Water Before Doing a Water Change
If your aquarium is at the high end of the acceptable range, 80 degrees, and you do a large 50% water change with 74 degree water, the average temperature will be 77 degrees in your aquarium. The sudden shock could lead to coral bleaching or die off as well as fish stress and illness. What's even worse is that most water that is not heated is often at or below 70 degrees, especially in colder climates, which could lower the temperature even more. The resolution is to heat the water before doing the water change. Even if the heater only gets the water within a degree or 2 of the aquarium temperature, the small change in overall temperature would only affect the system by 0.5 to 1 degree. This is much better for the health and stress of the tank, especially if doing this large of a water change.
Most of us do not have these extreme conditions when doing a water change. Generally our reef tanks are between 78 and 79 degrees, and we only do 10% - 15% water changes. That being said, the water in the mixing station at my home, before heating, is at 65 degrees. This means the water temperature would change by 1.3 - 2.1 degrees suddenly after a 10 - 15% water change. If I were to heat the water to even just 75 degrees, this would minimize the change in temperature to only drop 0.3 - 0.6 degrees, which results in significantly more stable parameters, especially when changing water weekly. Optimally, I would just heat the water to the same temperature as the water in the display tank. This way, the aquarium inhabitants won't notice any temperature fluctuations and will experience less stress!
For more information about Reef Aquarium Heaters, read my article Saltwater Aquarium Heater Guide for more information.
2) Stable Salinity in Reef Aquariums
This one may seem obvious in thought, but often goes overlooked; I admit that I have been guilty of this myself. Fish and corals require a certain concentration of salt in the water to breath and survive. Think of it as having a high humidity day where it's hard to breath outside. Though you will adjust eventually, this sudden change of walking in to this humidity causes stress on you similar to how sudden salinity changes will do so for your aquatic life.
What affects the salinity levels in reef tanks? The main causes are evaporation and water changes. Let's dive in to how to maintain this parameter.
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Aquarium Auto Top Off - ATOs
Adding fresh, RO water back to the aquarium as it evaporates solves the evaporation issue quite easily. Though adding water once or twice a day may be sufficient, depending on the amount of evaporation or the tank size, this may lead to frequent swings in salinity. The easy solution? An Auto Top Off Unit, better known as an ATO. An ATO is essentially just a sensor, frequently a laser or float switch, will turn on a pump to put fresh water in the tank until the level is met again. This will keep the salt levels constant all day, and all you have to do is make sure the fresh water bucket isn't empty.
Like anything else, these can always fail. If it fails off, there is not much concern as you will be able to add the water manually until you are able to fix the issue. Failing on however will lead to a drop in salinity, as well as likely tank overflow and major issues. This is a consideration by most ATO manufacturers ans as such, there are frequently emergency shut offs if the pump is running too long and / or sensors to turn the pump off if the water level is too high. Alternatively, you can pick up overflow sensors that would turn it off as well. My personal opinion is that the benefits outweigh the unlikely downfalls, as long as you set up an ATO with a safety shut-off of some sort.
If you don't know where to begin when selecting an ATO for your tank, here are a few good places to start:
For more information about ATOs, read my article Saltwater Aquarium ATO Guide for more information.
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Check Salinity Before Every Water Change
When finding that the salinity levels between the tank and the new water don't match, changes should be made to get these levels as close as possible. Like noted in the example above with the temperature change with water changes, the same applies to salinity in reef aquariums. The larger the change, and the larger the difference in these numbers leads to a larger change in the aquarium salinity. Therefore it is ideal to have both salinity levels as close as possible so you don't need to worry when doing water changes more often or even larger water changes.
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Inaccurate Salinity Measurements
Okay, again, seems obvious, but when did you last calibrate your measuring equipment? Refractometers should be re-calibrated every water change or two at the worst case. The calibration of this often takes a minute or less and can prevent stress in all of the aquarium life by minimizing salinity changes. Alternatively, a better measuring tool such as a Milwaukee salinity meter can be used and will need calibration less often.
Have you noticed that I DON'T talk about the hydrometer? That is because this means of measurement is so wildly inaccurate that it should not even be considered. Refractometers are easily available and not expensive, especially for the health of your reef tank. If you are still using a hydrometer, consider upgrading to a low cost refractometer. Though it seems expensive when just starting out, this will save you a lot of money fixing problems in the long run.
3) Aquarium Alkalinity Stability
Stable alkalinity in reef tanks is another simple yet very effective method of increasing coral growth. Though not as important as temperature and salinity, alkalinity swings will affect coral growth and health. There are a variety of ways to maintain stable alkalinity, including dosing 2 part (or 3 part) solutions, kalkwrasser, and calcium reactors. These topics are fairly involved and as such I will direct you to the following article:
Though I will not go in to detail on dosing, kalwasser, or calcium reactors, I will give a couple tips that can help with these methods.
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When Dosing, Dose Less More Often
Quite simple really. As long as there is some time between dosing the calcium and alkalinity components (30 - 60 minutes depending on your aquarium and flow) you should split the doses up in to as many parts as possible, keeping the alkalinity levels stable at all times. As an example, you could dose alkalinity every hour, on the hour, and calcium every hour on the half hour. This would need to be done in high flow areas of the tank and/or sump, preferably further apart. Though this can be difficult, depending on the amount you're dosing, it can lead to better coloration and growth of coral.
When dosing, in order to achieve this frequency of dosing, you will need to used a dosing pump such as the Jebao Dosing Pump. Alternatively just doing a search on Marine Depot will lead you to a variety of dosing pump options.
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Clean Equipment is Good Equipment
For the other methods of maintaining aquarium alkalinity, there may be less work to do on timing, but clean equipment is a must. Pumps can clog or slow down with time, and reactors can clog with debris. These should be cleaned often to ensure they are working effectively.
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Choosing a Salt Mix with Similar Parameters To Your Tank
Again we fall to the topic of water changes. When choosing a salt mix, it is important to choose one with an alkalinity level that most closely matches the alkalinity in your reef aquarium. This topic is well covered in the article Picking a Reef Aquarium Salt - Reef Aquarium Salt Parameters. There is also a table with the known parameters to help you choose the best reef salt mix for your aquarium.
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Measuring Alkalinity in a Reef Tank
One final note on maintaining stable alkalinity is measuring alkalinity. Alkalinity should be measured at least once, but preferably two or more times per week. The tests are often quick, a minute or less, and can inform you if anything is going wrong. Personally, I like to track my measurements a few hours after a water change as well as just before a water change. This lets me determine the usage over the week so I can make adjustments to my dosing numbers. Additionally quality test equipment is important for measuring alkalinity. I personally prefer and highly recommend the Hanna Checker, though I have also had success with the Red Sea Test Kit if you are not ready for the investment of the Hanna Checker.
Recommended Alkalinity Test Kits:
Conclusion
By incorporating these tips and tricks, and implement the recommended equipment, you will be a step closer to a stable reef tank. Stability will lead to better health for your fish and coral, and a better environment entirely.
Related Articles
- Saltwater Aquarium ATO Guide
- Saltwater Aquarium Heater Guide
- Understanding and Balancing Alkalinity, Calcium, and Magnesium in Saltwater Aquariums
- Picking a Reef Aquarium Salt - Reef Aquarium Salt Parameters
Thanks for Choosing Reef Stable
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About the Author
John Krenzer
John is a Software Engineer with a passion for saltwater aquariums, as well as the founder and president of Reef Stable. He started in the aquarium hobby as a child with a 20 gallon freshwater aquarium. His interest in aquarium life grew and in 2008, John set up his first saltwater aquarium.
Today, John maintains an over 300 gallon reef tank system, consisting of a 120g reef and a 210g reef. These large tanks are contained within the same system, sharing a sump as a means to reduce total maintenance and increase total water volume.
John writes articles for the blog as a means to learn about more reef aquarium topics. These articles act as a reference for the readers as well as himself. John updates these articles frequently to provide additional information or make corrections as new information becomes available.
If you would like to request an article, tank tour article, or to collaborate, let me know via the Contact Me Page!
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