Eco-Complete vs Flourite Substrate, Which Is Best?

When you think of an aquarium what do you think of first? Fish, decorations, food, and a heater or filter system? Most people, when they are looking at things for the bottom of the tank, go to gravel or colorful rocks. Not realizing that the “substrate” you put in the bottom can ultimately help their aquarium and their fish.

  • Eco-Complete is a highly porous grain, spherical in shape. This substrate contains live bacteria to quickly convert fish waste into natural food for your aquatic plants.
  • Fluorite is stable porous clay gravel for a planted aquarium. It is best suited for a planted aquaria but you may also use it in a saltwater or freshwater tank, safely.

Substrate affects water chemistry. It also helps with filtration and the well-being of the fish you keep in the tank. So, which is better for your tank. As of right now, I am going to say it is a personal preference. But we are going to investigate.

We are going to take a look at both types of substrates. I am going to research, investigate, and suggest which substrate is the best for your aquarium. I will give you more information on Eco-Complete and Fluorite. I will go over the uses, the cleaning, and which substrate is best for your fish.

What Does Substrate Do?

You want to choose what type of substrate you use, carefully. It isn’t near as easy to change as other elements of your aquarium. So, if you choose a substrate and then do not like the way it looks or performs, you will have to completely empty the tank to change it.

Substrate is available in all sorts of colors and materials, giving you many options when setting up your tank. But you want to choose wisely. You want something that has a good appearance, but more importantly something that is going to be beneficial to the fish and the overall health of your tank.

You can get colored substrate to go with an aquarium “theme” or to just give it a pop of color. There are also natural brown colors to make the aquarium more life-like, more like “nature.” You can also choose gravel, which is a place for beneficial bacteria to grow and aid in the breakdown of fish waste.

Your substrate, whether gravel or another type, allows beneficial bacteria to colonize. The substrate also allows for any live plants to take root. There are specific types of substrate that will provide key nutrients for your live plants.

Fish Habitat and Decoration

Substrate has many uses and purposes. It creates a natural fish habitat and is important for the fish who like to burrow. The substrate also makes your fish feel safe, they can root for food, and some fish will scatter their eggs throughout the substrate. If you have larger substrate then the fish eggs can fall in between pieces and be protected from other fish. 

Your substrate choice is going to contribute to the look of your aquarium. The substrate, when combined with other decorations, can produce a very appealing scene or theme in your tank. Making it attractive to look at. Some suggest choosing a substrate that will compliment the color of the fish who will make the tank their home. 

Substrate Material

As stated earlier, there is a wide variety of substrate materials. Gravel is the top seller in most pet stores. It comes in all sizes, colors, and shapes. Sand is the 2nd most purchased for aquariums.

You can also use crushed coral, larger rocks in conjunction with the gravel, or even marbles. But, marbles are not recommended unless you are just putting a few in the bottom of a fishbowl with a goldfish or a betta fish. They do not provide any help in the health or maintenance of the tank.

For overall water chemistry, filtration, and the health of the fish you want to research before you just grab a bag or two of the random substrate from the pet store. Some fish prefer a certain type of substrate, especially if they like to dig or burrow. There are other fish, like the Oscar, who need the sand or very fine substrate so that it doesn’t scratch their scales. 

Eco-Complete Substrate

Beneficial Bacteria from Eco-Complete

It can take up to a couple of months to grow beneficial bacteria in your aquarium. To maintain a well-balanced environment for your fish, beneficial bacteria is essential. One of the key benefits to Eco Complete is that it is pre-cycled. This means there is already beneficial bacteria growing before you add it to your tank. It is , of course, not a large amount but it does give you a head start on the process.

This product is actually wet-packed, so there is no need to rinse it before you add it to your tank. In fact, if you do rinse it, you are risking losing the beneficial bacteria that are already growing. Another benefit of the Eco-Complete is the fact that it has tons of little nooks and crannies, perfect places for the bacteria to thrive and grow. 

The more beneficial bacteria the better for the overall health of your tank and its inhabitants. Eco Complete is very rich in essential nutrients like; potassium, iron, zinc, calcium, and magnesium. There are also no chemicals, dyes, or coating added to the Eco Complete. Since this is an all natural substrate, you will never need to replace it. It will last the life of the tank.

How To Use Eco-Complete

Course Eco Complete almost instantly converts fish waste into natural food for your plants. It comes in black or in red, both of which are high in iron and do not contain laterite.

The sizing of the substrate varies throughout the bag. The black contains 0.25 to 7.00 mm pieces and the typical size for the red Eco-Complete is 3.0 to 6.0mm. It is suggested that you use 2 pounds of the substrate per 1 gallon of water. 

Eco Complete will not raise the pH levels in your tank. The coloration of the red Eco Complete enhances the color of your fish and reduces fish stress. You will have healthy roots, no chemicals, and optimum beneficial bacteria. 

Eco-Complete is excellent for starting the nitrogen cycle in your tank. However, it will raise ammonia levels. So, you do not want to add your fish to the tank until the cycle is complete and you check your pH level. The only real con that I have found, so far, is that it smells funny when you open the bag because of it being wet-packed.

Flourite Substrate

This substrate is made by Seachem. This is porous clay gravel for a naturally planted aquarium. It is best used alone, but you can mix it with other gravels. Fluorite is not coated or treated, therefore it will not alter your pH in the aquarium. This substrate will last the life of your aquarium, never needing to be replaced. 

Seachem Flourite is relatively new to the market but is becoming pretty popular in its own right. There are 4 Seachum substrates; Flourite black, black sand, red, and dark. The Flourite black is gravel with a grain size of 0.5 to 2.0mm. The black sand is, of course, sand with the grain size being under 1mm. 

Fluorite has magnesium, potassium, iron, and some other essential nutrients. This substrate is heavier and more stable than other soil substrates. The plants will suc up the nutrients through their roots. This comes pre-rinsed but it is recommended to rinse before you put it in your tank. During transport it can get tossed around, which creates dust in the bag. If it isn’t rinsed, your water will be cloudy.

There is also Seachem Flourite that is called Black Sand. There are 2 major, obvious differences, between the standard and the black; it is charcoal black and has a much smaller particle size. Because of the smaller particles, debris will build up on top of the substrate. There are no cracks for the extra food or the fish waste to fall in between, so all of that will build up on top and can be easily seen.

It also causes a little bit more maintenance on your part, because you don’t want anyone to see the built-up debris. It makes the tank look very unattractive.

How to use Fluorite

Whether you use the standard or the black sand, it is recommended that you rinse it first. Both types of substrate may cause some cloudiness upon initial use and during your water changes. The black sand is excellent for the fish who like to dig or to burrow.

In the standard Fluorite you have the option of choosing a red substrate, to give your aquarium just a touch of color. The black Flourite however, contains lower levels of iron, potassium and magnesium than the red. Sodium and calcium are much higher in the black sand fluorite. None of these will change the pH level of the water, but it is unknown if the extra calcium will affect the gH level. 

The black sand and standard fluorite will both enhance your fish and plant colors. They are also both great for growing your live plants, can be mixed with other substrates, and in both freshwater and saltwater tanks.

Fluorite Polished Gravel

As I was researching, I came across the Fluorite Polished Gravel. Used for any number of things, including in your aquarium. So this gives you just another Fluorite option, when it comes to your substrate. This is a mix of gravel stone and crushed crystals (Selenite Stick and Tumbled Crystal). There are 9 colors available, or you can purchase a mixed color bag. 

The Fluorite Gravel creates a beautiful and natural base for your aquarium. It provides quality filtration for your fish and your tank. Giving a good place for beneficial bacteria to colonize. Be sure to rinse it well before adding it to your tank. 


Fluorite or Eco Complete? This, as with any other substrate, or aquarium product is going to come down to personal preference. They both have excellent qualities for your tank and your fish. 

Recommended to be used alone and in a planted aquarium, you can mix both Eco-Complete and all varieties of Fluorite with other gravel substrates. You can also use them both in freshwater or saltwater tanks, safely. They are not going to harm the fish in any way. Both of them are beneficial to the overall health of the tank and the fish/plants. 

Of all of the reviews that I sifted through and people that I spoke to, both the Eco Complete and Fluorite perform the same. The only drawback to the Fluorite is the fact that your water will be cloudy for a few days. But should be clear by the time the cycling of the tank is complete, so it will be safe to add your fish. 

The biggest pulse of the Eco-Complete is that you can use it, right away, straight out of the bag. No rinsing is needed, and it is actually stated that it should NOT be rinsed before use or you will harm the beneficial bacteria that are already growing. 

Again, person preference will be the deciding factor in this debate. It depends on if you have fish, if you want extra maintenance, and overall look of the aquarium once the substrate is in. So choose wisely, as it is not changed easily and remember that both of these types of substrates will last the lifetime of your tank and will never need to be replaced because they are all natural.


I'm passionate about fish pets and love sharing everything I learn about them.

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