• Premium natural substrate for the planted aquarium
  • Good for the life of the aquarium
  • Rinse right in the bag (3.5 kg only)


Flourite® is a specially fracted stable porous clay gravel for the natural planted aquarium. Its appearance is best suited to planted aquaria, but may be used in any freshwater aquarium environment. Flourite® is most effective when used alone as an integral substrate bed, but it may be mixed with other gravels. Gravel modifiers such as laterite are not necessary. Flourite® is not chemically coated or treated and will not alter the pH of the water. Flourite® is good for the life of the aquarium and need not be replaced.

“The folks at Seachem have done a wonderful job responding to the needs of aquatic gardeners. Seachem has developed a complete line of well-researched products for the planted aquarium. My personal favorite is Seachem Flourite®. In my opinion this is the best product available as a substrate in the planted aquarium. It is easy to use, attractive, and the plants love it. Since setting up my first Flourite tank, I have used nothing but!”

Karen Randall Editor of The Aquatic Gardener

To determine the number of bags required for your aquarium, please note that each bag (7 kg, 15.4 lbs) occupies a volume of approximately 7,000 cm3 (425 cu. in.). To determine your desired volume multiply tank width by length by desired depth. This bag is sufficient for about a 5 cm (2 inch) deep bed in a typical 40 L (10 gallon) tank.


Although it is pre-washed, because Flourite® is a natural product, it may become dusty in transit and require rinsing before use to remove any residual dust.

NOTE: The specialized mesh bottom of the 3.5 kg size allows it to be rinsed right in the bag.

TIPS: When adding water to aquarium, fill slowly to avoid disturbing Flourite® substrate bed. Place a bowl in the aquarium and add water directly to the bowl, allowing water to overflow softly on to the gravel bed. Initial cloudiness is normal. To remove cloudiness, use mechanical filtration (such as filter floss). Clarity™ clearing. For an even stronger root zone and enhanced growth rates, add a 2.5 cm (1 inch) base layer of Onyx Sand™ to your aquarium before adding Flourite®.


3.5 kg, 7 kg

Mineral Composition

Aluminum 10,210
Barium 124
Calcium 195
Cobalt 6
Chromium 13
Copper 17
Iron 18,500
Potassium 2,195
Magnesium 2,281
Manganese 64
Sodium 223
Nickel 12
Vanadium 15
Zinc 29

Units=mg/kg, source: Plasma Emission Spectrometer, EPA Method 6010, Univ. of Georgia Chemical Analysis Lab

Wondering how many bags you will need for your project? It's easy to figure out with this gravel calculator. Just enter the length and width of your aquarium along with the desired depth of the substrate and click calculate. Note: The calculator will always round up. For example, you can't purchase 1.3 bags, so it will return 2 bags.

If you plan on varying the depth of your substrate, use an average depth as your desired substrate depth.

You require:

7 kg bag(s) or 3.5 kg bag(s)

A: Flourite inherently contains only micro nutrients and these are slowly released, many not released unless actively transported by the plant roots. Thus the substrate should be self-sustaining for many years and should never actually require replacement.

A: Depending on how dense the growth or how dense you wish it to be, the use of Flourish,(foliar feeding), Flourish Tabs (root feeding) and Flourish Iron can be useful and helpful beyond the substrate itself, but are not necessities.

A: Flourite will work fine with an UGF. Flourite is ideally sized and has a clay based composition (including minerals such as iron and manganese) that is ideal for plant growth. Flourite will not soften or decompose to an unsuitable state. In addition, Flourite has an attractive, natural appearance.

A: Flourite is a red clay based gravel that is rich in ferric iron. Comparing Flourite and laterite on the basis of their iron content alone is not a really valid comparison since they are really quite different products (the old apple and oranges argument). Their iron content is going to be roughly pretty similar, but with each the actual content can vary from lot to lot. Since we don't market it as an iron supplement, we don't make any claims on exactly how much iron it delivers to the water per se. What it does do though is provide a rich source of iron (more than enough to last years) for rooting plants... the plants are able to extract the iron from the Flourite. There are also other features of Flourite which make it superior to laterite: (1) laterite is intended as a substrate supplement, i.e. you add it to your gravel... by itself it is not a suitable substrate because it will quickly break apart into, well, dirt (2) Flourite is by itself a suitable substrate because it remains solid, does not fall apart,and can be cleaned and gravel vacuumed without unduly upsetting the substrate.

A: We are currently investigating this claim and will make our findings public when we have all the facts. However, all iron containing substrates (even laterite) contain around 5 ppm of arsenic (as insoluble ores (aresenopyrite or orpiment)). The keyword here is "insoluble" because if either of these ores were in any way soluble the water would contain far beyond the 0.05 - 12 ppm toxicity that plants show toward arsenic. The fact that thousands of people use this product in their planted tanks without a single incident of plant death (on the contrary, all we hear are stories of fantastic growth!), is a strong indicator that no arsenic is being leached.

A: It is possible to experience an excess of particles/dust from this product due to frictional action in packaging and shipping. Flourite Red is an ore with a rich mineral composition and is not chemically coated. Even though some small particles washed away, the product is completely viable and will still offer the same benefit. A better way to add this to an established aquarium is to add small amounts at a time a half day to 24 hours apart making sure these small amounts are rinsed thoroughly. You can also use a water clarifier like our Clarity to clump any small free floating particles together making it easier for your mechanical filter to catch. Your cartridges/floss will tend to clog from all the particles being trapped and will need rinsing or replacing regularly.

A: Flourite will not break down under long term aquarium use.Though it is a fracted clay based substrate, this clay is as hard as a rock - not soft. For all intents and purposes, it is a rock. This substrate is made up of a rich mineral composition, not just coated with a fertilizer so your plants will derive a long term benefit from this substrate.

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0493 Flourite 3.5 kg
0495 Flourite 7 kg