High-capacity RO membrane filter
Color-changing DI filters
Efficient TFC membrane
Pressure gauge included
4-stage water filtration
Highly-efficient TFC membrane
Color-changing DI filters
A reverse osmosis unit is a worthy and necessary investment for any reef tank or saltwater aquarium owner. Saltwater organisms can be extremely sensitive and they require a safe, hospitable, and healthy environment to be able to thrive. A RO system provides just that, and it’s particularly beneficial for corals because it prevents the overgrowth of algae. However, with so many choices available, it can be tricky to decide which RO system is best for your needs. Our review of the best RO systems will help you narrow down your search.
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With advancements in technology, modern reverse osmosis units for aquariums offer plenty of perks and a way to obtain extremely clean water that’s free of almost any contaminants you can imagine. With such a wide selection of products, it can be difficult to decide which one is right for you, especially if you are a novice when it comes to reef tanks or saltwater aquariums. However, there are some factors you need to take into account when purchasing these systems, such as the number of stages it provides, the quality of the membrane, capacity, and ease of use.
Reverse osmosis systems typically come with 3, 4 or 6 stages of water filtration, while some even offer additional filtration options for extremely pure water, such as UV filters or alkaline filters. The minimal amount of stages you need is 3, anything less is considered to be of poorer quality and it could compromise the wellbeing of your fish because the membrane isn’t protected enough. The 4-stage option is the one that most aquarium enthusiasts go for, as it provides effective water purification consisting of the following: a sediment and carbon pre-filters, the membrane, and the DI filter. The higher stages involve adding another DI filter or a carbon filter to further purify the water and protect the membrane A sediment pre-filter protects the membrane and it filters larger particles of sand and other sediments, while a carbon filter is responsible for removing chlorine, which is a common ingredient found in tap water. The membrane is essential part of a reverse osmosis unit and id does most of the job when it comes to removing total dissolved solids (TDS), which include organic compounds, heavy metals, and salts that the water contains. The fourth stage is the deionization process, which involves restoring the water’s balance by adding minerals and getting rid of any remaining contaminants that weren't removed during the previous stages. The DI filter’s resin contains hydrogen molecules that get traded with chemical molecules, hence making the water purer. Once a resin releases all of its hydrogen molecules, it’s time to get a new one.
The membrane is the focal point of a reverse osmosis unit because it handles over 95 percent of chemical removal. However, it’s extremely sensitive and permeable, which is why it should be protected by the filters that come before it, as their job is to remove bigger particles. It’s extremely important that a membrane is made of a high-quality and durable material, so that it can perform an effective filtration and last for a longer period of time. The most effective type of membrane is the one that’s made of thin film composite (TFC) as it removes 94-98 percent of total dissolved solids. TFC membrane is more often found in units with 6-stage filtration because it can get damaged easily by chlorine, hence the need for a carbon filter that removes this substance from water. Another option is a cellulose tri-acetate (CTA) membrane, but this type has a lower TDS removal score compared to TFC membrane that ranges from 88 to 94 percent. Also, this membrane only functions with chlorinated water, since the lack of chlorine would cause the growth of bacteria on it, so they are never used in 6-stage filtration units.
The capacity of a reverse osmosis unit is measured by the maximum amount of gallons it produces per day. Typically, RO units with a faster water output will have the capacity of 100 GPD and above. Generally, systems with faster outflow rate are a better option because they take less time to fill the tank, which will also save you some time, as you won’t have to sit around and wait long for the tank to become full.
It goes without saying that you should choose a product that is easy to install even if you’ve never used it before. Majority of reverse osmosis units are pretty easy to set up and they come with all the equipment you need. They also include instruction manuals and sometimes even video support. Another important feature is how easy it is to maintain a reverse osmosis unit. You’ll want a product that allows for easy installation of new parts in case of breakage. For example, some RO units come with twist-in cartridges that can easily be replaced, without the use of tools.
A RO system can last for an indefinite period of time as long as you regularly replace the old parts with new ones when they wear out. On average, membrane can last from 2 to 5 years, depending on the nature of water it filters. Carbon filters should be replaced every 6 to 12 months for optimal performance.
RO units don’t require electricity to keep them running as they operate with the help of water pressure. However, if you add UV lamps or pressure booster pumps to your system, these items will require electricity to power them.
Total dissolved solids are commonly contained in water and they encompass substances such as salts, heavy metals, and organic compounds. Having low amounts of TDS in your tank won’t necessarily cause you problems, but higher amounts of it can lead to algae buildup, which can be harmful for fish and corals. It’s a good idea to aim for having zero TDS in your aquarium, which can easily be achieved if you invest in a quality reverse osmosis unit with a high-rejection membrane that will be able to remove the solids completely. Fortunately, it’s easy to measure the amount of TDS your tank contains so that you can reduce the number if necessary. Many RO units come with built-in TDS meters, but if the one you purchased doesn’t, you can buy it separately. These devices are affordable and reliable, and they are necessary for maintaining optimal water quality for your reef tank or saltwater aquarium.
As we’ve mentioned above, the number of gallons produced per day refers to the flow rate of water that gets released, and how much you need will depend on the size of your tank, whether you use a storage tank as well, and how often you flush the water. If you want to determine the minimal amount of GPD you need, you have to divide the size of your tank in gallons by the number of days between water changes. However, if your RO system is connected to a water storage tank, you’ll be able to produce a higher number of gallons than the minimum you need, so you can change the tank water by pulling from your storage container. The RO systems that provide faster water output will save you some time waiting for your tank to fill, so they are generally a better choice, although you can opt for slower alternatives if you have free time at hand, speed will not affect the quality.
RO water and RO-DI water are similar in many respects, but they also have a few key differences. RO-DI stands for reverse osmosis deionization, so water that goes through this type of filtration goes through the process of deionization in addition to reverse osmosis. This means that the water goes through additional filtration stages that enable it to become extremely pure as they eliminate any remaining water pollutants. Also, through the process of deionization, the water receives back some of the nutritious minerals that are necessary for maintaining a hospitable and safe environment for the fish and plants.
Water pressure is essential because it’s responsible for the flow of water through the membrane and for the flushing of contaminants away. Low pressure can hinder water production and it can damage the membrane. The optimal amount of pressure for a RO unit is 60 psi. If you have a pressure below 40 psi, it probably won’t be enough to keep the system working, and you’ll need to increase the pressure with a pressure booster pump.
Adding a water softener can make the membrane last longer. The sodium that gets added to the water through the softener is much gentler on the membrane as it is able to remove up to 98 percent of this substance.
When saltwater evaporates from a tank, it leaves the salt behind, so you should refill it with freshwater to keep the salinity level unchanged.
After reviewing the options above, you should be able to have a clear picture on what type of reverse osmosis unit you need. Take into account the size of your tank and think about how many filtration stages you actually need. Also, look for products that are sturdy and have a quality membrane that will be able to filter your water efficiently for years to come.