How to Remineralize Ro Water for Aquarium

The process of remineralizing RO water is very simple and easy to accomplish the task. There are various methods that can be used depending on the desired outcome, but all require the same basic steps: adding minerals back into the water to restore balance. This post will discuss how to remineralize ro water for aquarium with common household items or purchase one premixed for convenience. You’ll also find out why it’s important to do so!

How to Remineralize Ro Water for Aquarium

Reasons to Remineralize Ro Water for Aquarium

Remineralizing RO water will replenish the beneficial minerals that are essential for reef health. By using a remineralizing system, you can reduce stress on corals and invertebrates, enhance growth rates of stony corals, enhance skin coloration (reduce “muddy” colors), increase density and strength of skeletons (useful for SPS corals), and increase survival rates of new frags.

Additionally, carbon filters will remove most major minerals from reverse osmosis water, so using a mineralization system is essential to maintain proper nutrient levels in an aquarium.  

Why Use a Remineralizing System?

It’s already known that many major minerals are essential for healthy aquarium inhabitants. In fact, the majority of major and minor elements required by corals and other invertebrates can be supplied from marine-sourced substrates or water directly.

Minerals Are Essential for Aquarium

However, it is important to keep in mind that there is a wide variation in individual elemental requirements. Many reef aquarium residents, including corals, especially SPS corals, may require specific minor or trace elements that are not available through water changes alone.

As an example, calcium is required for the deposition of skeletal material for all scleractinian corals. The importance of calcium in this regard cannot be overstated; even if the availability of carbon and nitrogen were to be unlimited, the growth of corals and other calcareous reef invertebrates would be severely restricted without adequate calcium.

7 Ways On How to Remineralize Ro Water for Aquarium

Way 1: Using Drip System

The most convenient way to remineralize RO water is by using a drip system. It’s easy, efficient, and the only real downside is having to purchase multiple 17-gallon storage containers. Depending on how large your tank or sump is, this could become rather costly over time.

Way 2: Using Tablets

Another way to remineralize RO water is by using tablets with a reactor. This method is also very effective but will require some additional equipment not required for the drip system. Such as the minerals are already dissolved in tablet form, so you don’t have to worry about measuring out specific amounts of each mineral per batch. Tablets are also more cost-effective over time by reducing the need to purchase multiple 17-gallon storage containers.

Place a tablet in a reactor once per week, and it’ll take care of the rest! Awesome, right?

Way 3: Using Premixed Packets

Alternatively, you can also use premixed packets that come in different ratios, such as 2:1 (Calcium to Magnesium) and 4:1 (Calcium to Alkalinity). This method is often the most cost-effective but requires a larger initial investment.

Way 4: Using Coral Snow

Coral Snow by the Red Sea is another popular method of remineralizing RO water for aquariums. Although this method does not provide a full range of minerals, it is usually used to enhance corals’ coloration and overall health. Shake up the contents of one packet with 10g RO water until fully dissolved.

Using Coral Snow

Way 5: Using Seachem Replenish

Another method that many aquarists use to remineralize RO water is using Seachem Replenish. This is an all-in-one additive that provides not only minerals but also buffers pH and alkalinity levels. Shake the bottle before use to ensure even distribution of minerals, then add 5ml per 20 gallons of RO water to be remineralized.

Way 6: Using a Calcium Reactor

A calcium reactor is a great piece of equipment to add to your sump or even in addition to a drip system. If you don’t have a protein skimmer, this will also give you much more control over how much and how often minerals are being added to your water. The only downside would be an initial investment, but many can agree that it’s well worth the money over time.

Simply add saltwater (premixed with additives) to the calcium reactor and adjust flow to achieve desired consistency. This method is great for maintaining levels of calcium, alkalinity, magnesium, strontium, and iodine.

Way 7: Using a Diffusion System

Last but not least, you can also use a diffusion system. This method is probably the least cost-effective but has many benefits, such as requiring no additional equipment to operate other than a pump and air stones. Not only that, but it can be very helpful for preventing detritus from entering your main tank. If done properly, the only real downside would be monitoring levels of calcium, magnesium, and strontium manually.

Mix water from your main tank with saltwater (premixed with additives) in one container before transferring it into another container that’s connected to an air stone via airline tubing. The continuous movement of fresh saltwater through the air stone will create fine bubbles that dissolve into the water, releasing calcium, magnesium, strontium, and iodine ions.

Tips and Warnings


  • Make sure your water is around 80-85 degrees Fahrenheit before using any of these remineralizing methods. The warmer the water, the faster the diffusion process will be.
  • Test pH levels regularly to ensure they are within acceptable ranges (6.8-8). Adding minerals will lower pH, so you may need to adjust accordingly with an alkalinity supplement.
Test Ph Levels Regularly
  • Ensure your pump’s flow is not too fast for smaller tanks and tanks with delicate corals that may be sucked into the filter impeller, aquascape, or pump strainer.


– Make sure you use a protein skimmer before adding minerals to prevent the water from becoming cloudy.

– Avoid using additives such as calcium, magnesium, and strontium if you have phosphates in your aquarium because it could cause an algae bloom.

– Measure the flow of your air stones to make sure they match the rate of diffusion (the bubbles should dissolve into the water within 10 minutes). If too much or not enough air is being released into the system, bubbles will begin to rise to the surface, which could cause an algae bloom.

– If you see any algal growth on your aquarium glass, rocks, substrate, etc, check the water’s levels of calcium and magnesium before adding nutrients to your tank. This usually occurs when the water contains too much of one or both minerals.

– Avoid adding too many additives at once as it could cause algae to bloom and damage the livestock’s delicate systems.

Frequently Asked Questions

Do You Have to Remineralizer Ro Water for Fish?

No. Fish can survive in tap water, which is usually a mixture of natural minerals and carbon dioxide. However, if you have hard water containing large amounts of calcium and magnesium ions, the fish will be healthier by adding some re-mineralized water to their tank.

Where to Buy Ro Water for Aquarium?

The best place to buy RO water is from a local store or online.

If You Are Looking for More Information on Buying Ro Water, Here Are Some Helpful Tips :

  • Research the brands that have good reviews online and find one that fits your budget.
  • Ask the seller if they offer a guarantee and how long it lasts.
  • Get in touch with them by email or phone if you have any questions about their product or service before making a purchase.

Can We Use Ro Waste Water for Aquarium?

Ro wastewater is a very useful resource for aquariums because it contains no nutrients. This makes it an ideal solution for those looking to use their ro wastewater in their tanks without worrying about the consequences of using tap water.

The most important thing to remember when using wastewater is that you should never introduce any new fish into your tank with this type of water because it can kill them.

Another point to consider is that if you have an algae problem, you should only add to wastewater when cleaning your tank and not replace normal tap water

Replace Normal Tap Water


In summary, there are many ways on how to remineralize ro water for aquarium. The most effective of these options is to use a product containing calcium and magnesium ions dissolved in carbonate salts such as potassium bicarbonate or sodium bicarbonate. These products can be purchased from your local pet store at a relatively low cost. They will provide both hardness and alkalinity, which help combat pH swings while increasing the number of ionized minerals available for absorption by aquatic life. Fish need plenty of fresh, clean water, so it’s important to take steps now before problems arise later on down the road! Thank you for reading our article. If you have any questions or concerns, please leave a comment below.

You can also read it: How to Clean Aquarium Gravel Without a Siphon

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