April 22

Best RO-DI Systems for Reef Tanks


RO-DI Systems

RO is the term for reverse osmosis, and the RO-DI system means reverse osmosis by deionization. RO or Reverse Osmosis is the potential purification process for a reef tank that utilizes a multistage filtration process. Thus the R0-DI system involves osmosis with an extra stage of deionization, providing the best results for your reef tanks.

The DI stage of filtration allows your tap water to reduce to ZERO TDS (total dissolved salt).  The popularity of this system is getting enhanced with time.

As the water passes through the deionization cartridge, the synthetic resins remove the positively and negatively charged ions and replace them with the hydrogen plus (H+) and hydrogen negative (H-) ions.

The process of purification essentially alerts the molecular structure of water. The most recommended RO DI systems for reef tanks involve 4-5 stages to filtration level to get the best quality water.

If you are a new aquarium hobbyist, it’s very significant that you should know the pros and cons of the RO DI product for your reef tanks. There are various types of products, and each of them has its own significance. This article will allow you to have useful knowledge about how one should implement a powerful RO DI system in the reef tank. It will also throw light on why you should opt for an RO-DI system for the maintenance of your reef tanks.

RO DI Systems for Reef Tank Reviews 2021

1) Liquid Gen 5 Stage Reverse Osmosis and Deionization RO-DI

Liquid Gen 5 Stage Reverse Osmosis and Deionization RO-DI


The product is great for the reef tanks as it’s a preassembled system meant for easy installation. This has leak-free fittings, which are pre-tested in the laboratory, and comes with a two-year manufacture warranty.

With a 5-stage filtration system, the product is easy to install and users report it takes just 5 minutes to get the product assembled.  The membrane will be flushed in 30 minutes as instructed. The water tests are done at 0ppm every time.


  1. It is 16 *6 *16 inches in dimension.
  2. It weighs 14.6 pounds.

The tap water reads at 89 ppm while the waste reads at 145 ppm. The product is updated with a high rejection reverse osmosis membrane having a capacity of 75 gallons per day.  In case, you are already using the product, the manufacturer will add an auto shut-off valve and also check the valve at their cost.


  • In case you are looking for a good RO-DI, this will be a perfect choice. This will definitely not give way and stop working like the rest. The product is much appreciated by the users and they say it’s a cheaper option, as fish stores tend to get costly after buying gallons of water from outside.
  • The product is useful as it gives liberty and alerts the user on when to change the filters.
  • The user can make use of the total quantity of water whenever he wishes. They also say that it’s fantastic and it is portable enough to be taken to your neighbor’s house for filling the buckets.
  • The overall unit is sturdy, reliable, and user-friendly.


  • Although the product claims 0 ppm, it doesn’t even come close to that.
  • Customers complain about after-sales customer services.

2) Koolermax 6 Stage RO +DI for Aquarium and Reef Tank

Koolermax 6 Stage RO +DI for Aquarium and Reef Tank


    The system comes with an RO unit, pressure gauge, installation hardware, and all filters along with it. The product includes an auto shut-off valve so that when the output is closed, the input can be easily turned off. The pressure gauge is included and can efficiently read the operating pressure.


    1. The system comes complete with all the filters, membranes, pressure gauges, installation hardware, and also tubing.
    2. The system has an RO unit, pressure gauge, filters, and installation hardware.
    3. They include an auto shut-off valve so that when the output is turned off, the input will also be turned off.
    4. The pressure gauge is included and reads operating pressure and also to replace the bottom 3 filters.


    • Users say that the product can work for four months without a single servicing.
    • The user recommends installing a dual inline TDS meter, which could be used for the TDS readings before and after the deionization procedure.


    • The resin is too small if your TDS is 300 for your faucet.
    • Filters are expensive, and their shipping is also costly.

    You can also use a permeate pump, in case you have used a pressurized tank. The more the pressure, the lower is the TDS, and it has a higher rate of water collection. For a better result, make sure you attach a TDS meter to verify things are working as they should have been.

    Hobbyists have recommended this product for fish lovers. The unit generally comes pre-assembled. It can very well be connected to a garden hose also. The amazing 40-gallon fish tank is ideal for breeding tanks. The users say that you have to careful with the membrane and tubing. You can even install a flush kit that varies from cheap manual to costly automatic. This will definitely increase the life of the RO membrane, as well as increase the life of the DI resin. You will get cleaner water overall.

    3) Liqua Gen Portable 6 Stage Dual-use RO DI System for Reef Tank

    Liqua Gen Portable 6 Stage Dual-use RO DI System for Reef Tank


    The product helps to restore minerals in the reef tank lost in the RO process. The quality of clean air is improved by adding the necessary minerals for the proper development of humans and also minerals. The minerals added to the system are magnesium, calcium, sodium, potassium, and many others found in natural water.


    1. The manual flush valve makes this system superior to the others.
    2. The product involves high rejection reverse osmosis. This is a pre-assembled system and takes about 5-10 minutes to install.


    • Users say that the filters are cheap and there can be up to 3 supplies per year whereas other companies generally overprice their filters.
    • The users can opt for the auto shut off, float switch, or meter, which can you can pick up at a fairly cheap price.
    • The product is meant to build to last. It’s easy to install and fairly priced. There is no observed sign of the product being brittle or discoloration even after two years.


    • The product doesn’t require a particular set of filters but it’s fairly universal. The portable RO filter does not come with a shut-off valve but a saddle valve.
    • You need to add an Aquatec ERP pump or the water saver kit.

    4). RO/DI Reverse Osmosis Dual DI Aquarium/Reef System

    RO/DI Reverse Osmosis Dual DI Aquarium/Reef System


    The product is a reverse osmosis system combined with a DI after the filter, giving the lowest TDS reading for the aquarium water supply. The DI resin is necessary to dissolve the TDS (total dissolved solids) to zero and basically, it’s the last stage of the RO/DI unit. There is basically no need to use the expensive proprietary DI cartridge. You can obtain a constant supply of high purity water simply using two cartridges in a series.


    1. Six-stage RODI aquarium system having 150 GP membrane.
    2. Dual DI refillable color changing media cartridge.
    3. Reverse osmosis combined with a dedicated DI after the filter.

    The first cartridge is allowed to be depleted followed by the next one. While the new cartridges are placed in the polishing position, the remaining is placed into the ‘roughening’ position.  The complete utilization of the exchange capacity is observed, which lowers the operating cost and increases the average quality.  The clear cartridges are refillable.  The RO along with the added nutrients are good for plants and animals as well.


    • Users are basically satisfied with the buy. Having consistent long-lived materials and elements, it is clear that some had no difficulty using it for the last 30 years.
    • It’s easy to install variety and the quality of filters is also excellent.
    • This RODI is an excellent system at a low price. Users are happy with the performance and it improves the quality of aquariums which support 65 gallons of water as well.


    • The sediment, GAC, and carbon block filter need to be changed regularly or at short intervals.
    • The membrane should be good for at least 3 years of average use.

    5). Aqua FX Barracuda with RO/DI Aquarium Filter

    Aqua FX Barracuda with RO/DI Aquarium Filter


    This 4 stage Barracuda comes with a 2-micron chlorine guzzler carbon filter and the system features a high low and high rejection TFC membrane. It includes a pressure gauge that allows unsafe ranges. The product is supplied with a ¼ inch hose bib adapter.

    The system includes all features like high flow, high rejection, and Aqua FX TFC membrane. It also quickly connects fittings and a filter range, which is meant for easy cartridge replacement. The product can handle 50 gallons per day. The product comes with a connector that connects with a tap outside and it removes chlorine too.


    • The installation is pretty easy, with no leaks that provide 0 TDS water.
    • The wastewater can be a bit more, but it works in the same way.
    • The build quality is a good one and can fill a 5-gallon bucket in one hour. The unit is not a fancy one, but generally comes with all requirements and produces 0 TDS measurement.
    • You can easily use the product in your bathroom sink.


    • It has a garden hose hook but requires an adapter from the local hardware which connects your faucet to the hose and the filter ultimately.
    • The warmer the product becomes, it has to get its filter replaced.

    What are the Common Specifications of the RO-DI System for Reef Tank?

    1. The RO DI system is about 7 pounds in weight and is 5*10.2*14.8 inches in dimension.
    2. The product comes with a 5-stage advanced filtration system like biological, chemical, water stabilization, oxygenation, and mechanical. The tank can hold up to 8 gallons of water.
    3. It is usually provided with a 12V transformer, air pump, air stone, water conditioner, a beneficial bacteria liquid, filter cartridge, and LED lights.
    4. It is built with acrylic and is remarkably stronger. It’s 93% transparent and has crystal water. The ceramic media helps provide biological filtration.
    5. The RO DI membrane is just one that performs reverse osmosis, or might be pushes water through it in order to remove any heavy metal, and also traces the element with other dissolved solids from the water.

    The popularity of the product in the market is due to the fact that the aquarium water will not be devoid of nutrients and minerals mainly.

    Why Do We Need RO-DI System for Reef Tank?

    In case you require the perfect marine environment for your saltwater fishes, you will require a successful saltwater aquarium relying on a strong foundation. Even if there are traces of compounds in the aquarium, it can contaminate the entire composition of the reef tank. Even a low level of nitrates can cause algae to bloom and also proliferate throughout the saltwater aquarium.

    The success of the reef tank depends on how much you maintain the delicate balance of the water parameters. If you mix sea salts with tap water, you are actually getting an approximation of the ocean water, but you cannot actually replicate it.

    The procedure of reverse osmosis helps in the elimination of fluorides, benzene, arsenic, calcium, lead, copper, and also pesticides that may remain dissolved along with organic and inorganic solids. The reverse osmosis system is actually helpful in stripping some specific compounds from the water, thereby making it additionally helpful for the aquarium owners.

    Once you have successfully obtained the mineral-free water that is produced by reverse osmosis, you have to regulate the water profile that best matches your fish’s requirement. The most important parameters of the water aquarium chemistry are the general hardness, carbonate hardness, and also maintaining the pH of tank water.

    Things to Keep in Mind While Buying RO-DI System for Aquarium?

    Buying RO-DI system for your reef aquarium could be advantageous in a number of ways. But there are certain facts to be kept in mind while buying the product.

    • The budget is a very important factor. Make sure that the product you buy should fit into your budget.
    • The RO-DI is bigger in size, so make sure that they have enough space to be kept comfortable.
    • Water is passed through four stages so that whatever you obtain is absolutely clean and clear water.
    • The third stage involves the usage of DI cartridge, which is a special membrane and removes the nitrates, silicates, phosphates, and other compounds. There are several types of membranes that could be used in the RO units, but the most frequent ones are the thin film composite (TFC).  The water passing through the system is usually sent to the storage tank.
    • Keep in mind that calcium is a very important component in aquarium salt. They are used by the corals and other invertebrates that would take their stony skeletons. The concentration of calcium in reef aquariums should be 440 ppm.
    • You must keep into stock the various fish water dechlorinating products which are available in the market that removes chlorine element but fail with other chloramine compounds. Hence, you will be required to use a formulation that specifically removes chloramines. Only then will the water be fit for fish consumption.


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