Fluval Stratum – 6 Key Benefits for Plant Growth Explained for Aquascapers and Planted Tank Hobbyists

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Fluval Stratum is an aquarium substrate designed specifically for planted freshwater tanks. It is made by the well-known aquarium brand Hagen.

There are two different varieties available:

  • Fluval Stratum Plant: This is the original formula optimized for aquarium plants. It is a brownish-red color.
  • Fluval Stratum Flora: This is a newer variety with added nutrients and higher CEC for maximum plant growth. It has a rich black coloration.

Both types are formulated with volcanic soil as the base. This gives Fluval Stratum some unique properties that set it apart from plain gravel or sand.

Some of the key benefits of Fluval Stratum include:

  • Nutrient-rich composition: The volcanic minerals provide a rich source of important nutrients needed for lush plant growth like iron, potassium, magnesium and calcium. This means no need to dose liquid fertilizers.
  • Promotes strong root systems: The porous structure and mineral content nourish plant roots allowing them to spread and anchor firmly.
  • Softens water: Fluval Stratum helps lower pH and water hardness, ideal for planted shrimp tanks.
  • High CEC capacity: This allows the substrate to absorb and store nutrients from fertilizers and fish waste to feed plant roots.
  • Long-lasting fertilization: The nutrient-rich composition releases minerals slowly over a long period of time. No need for root tabs for 1-2 years typically.
  • Natural look: The dark earthy colors and fine grain texture lend a naturalistic look perfect for aquascaped layouts.
Fluval Stratum

With its combination of strong nutrient content, CEC capabilities, and pH lowering properties, Fluval Stratum offers a comprehensive all-in-one substrate solution for planted aquariums.

How Fluval Stratum Works

The key to Fluval Stratum’s effectiveness lies in its unique volcanic soil composition.

The porous volcanic particles provide an abundant source of essential minerals including iron, magnesium, potassium and calcium. These minerals are released slowly over time, providing a steady nutrient supply to plant roots.

The porous structure also creates a large surface area and spaces that trap fish waste and fertilizer residues. This allows Fluval Stratum to absorb and store nutrients through its high cation exchange capacity (CEC). The stored nutrients can then be exchanged with plant roots as needed.

In addition, the volcanic materials in Fluval Stratum help lower pH and soften water by releasing organic acids and negatively charged ions. This helps replicate the soft, acidic conditions found in most aquatic plant habitats.

The lowered 7.0 pH is perfect for soft water plants like tetras, rasboras, and most aquatic plants. The acidic conditions are also very beneficial for dwarf shrimp, helping their molting and overall health.

However, Fluval Stratum would not be suitable for African cichlids, livebearing fish, or other species that prefer hard alkaline water. It’s formulated specifically for planted tanks.

Between the direct nutritional content, CEC capabilities, and water chemistry adjustments, Fluval Stratum creates ideal conditions for lush plant growth. It works as a complete all-in-one substrate solution right out of the bag.

Using Fluval Stratum in Planted Tanks

While Fluval Stratum makes it easier to set up a thriving planted tank, there are some important tips to follow when using it for the best results:


  • Rinse the substrate extremely well before adding it to the tank. Fluval Stratum tends to be quite dusty when first opened and rinsing will help avoid cloudy water.
  • Add the rinsed substrate slowly and gently to avoid stirring up dust. Use a plate or newspaper to diffuse the water flow when filling the tank.
  • Allow the tank to cycle completely before adding any livestock. Fluval Stratum will leach some ammonia at first so patience is key.


  • An ideal depth for Fluval Stratum is 2-3 inches at minimum. This allows room for plant roots to spread out.
  • For heavy root feeders or carpet plants, using a deeper 4+ inch layer can be beneficial. This ensures plants have a large nutrient reserve.
  • Slope the substrate higher in back and lower in front for an aesthetic look.

Plant Selection

  • The softened water and acidity of Fluval Stratum is perfect for carpeting plants like dwarf hairgrass, Monte Carlo, and glossostigma. These plants thrive in the plentiful nutrients.
  • Heavy root feeding plants like Amazon swords, crypts, and anubias will derive great benefit from Fluval Stratum’s mineral content. Their roots penetrate deep into the substrate.
  • Mosses, ferns, and epiphytes can attach well to hardscape and draw nutrients from the water column. Floating plants also do not require substrate.
  • Avoid very hard water loving plants that prefer alkaline conditions. Vallisneria may also spread too aggressively in the rich substrate.


  • Expect Fluval Stratum to provide 1-2 years of nutrients before needing root tab supplements in the areas around heavy root feeders.
  • To extend the lifespan of nutrients, use a nutrient-rich aquarium soil underlayer topped with Fluval Stratum. This combo can last 3+ years.
  • Perform regular water changes and gravel vacuuming to keep Fluval Stratum nutrient levels replenished.

Fluval Stratum in Specific Tank Setups

The properties of Fluval Stratum make it well-suited for certain popular planted tank configurations:

Shrimp Tanks

The lowered pH and soft water parameters created by Fluval Stratum provide nearly perfect water conditions for dwarf shrimp like Cherry Shrimp and Crystal Red Shrimp. The abundant biofilm growth on the porous grains gives shrimp plenty of grazing spots. The shrimp will thrive and show vibrant colors in this environment.

Betta Tanks

Bettas also appreciate soft, acidic water which Fluval Stratum reliably provides. The natural earthen look enhances the bright colors of betta fish. Fluval Stratum allows lush plant growth to offer cover and reduce aggression in a betta planted tank.

Low-Tech Planted

Fluval Stratum can sustain long-term plant growth even without added CO2 injection in low-tech setups. The built-in fertilization lasts longer than other substrates in low-tech conditions. The added nutrients allow plants to flourish with just light and no complex fertilizer mixes needed.

Breeding Tanks

The dense plant growth and softened water enabled by Fluval Stratum creates excellent conditions for breeding many species of fish. Quality spawning sites and good water parameters lead to higher fry survival rates.

Fluval Stratum is highly versatile and can be used in nearly any planted tank setup. But its properties make it particularly well-suited to these popular aquascaping configurations.

Fluval Stratum Compared to Other Substrates

How does Fluval Stratum stack up against some other common aquarium substrate options? Here’s an overview:

Vs. Gravel or Sand

  • Plain gravel or sand lacks any substantial nutrient content. Fluval Stratum is much more nutrient-rich and beneficial for planted tanks.
  • Sand is prone to compacting over time which can starve plant roots. Fluval Stratum maintains its porous structure.
  • The grain size and shape of Fluval Stratum is better for anchoring plant roots than smooth gravel or sand.

Vs. Other Aquasoils

  • Aquasoils like ADA Aquasoil and UNS Controsoil offer similar properties and benefits to Fluval Stratum. They can be seen as higher-end options.
  • Fluval Stratum provides much of the same nutrient concentrations and CEC capabilities as aquasoils for a more affordable price point.
  • Other aquasoils do allow more customization of layers and parts. Fluval Stratum is a simpler all-in-one product.

Vs. Inert Substrates + Fertilizer

  • With inert substrates you need to regularly dose liquid fertilizer and root tabs to feed plants. Fluval Stratum provides nutrition by itself.
  • Having a nutrient-rich substrate means less work managing separate fertilization. But you have more control with customized fertilizer mixes.
  • Flora and Fauna varieties allow some customization, but overall Fluval Stratum simplifies the substrate and fertilization process.

While pricier than plain gravel or sand, Fluval Stratum offers comparable performance to the top aquasoil brands for a more reasonable cost in most cases. It hits a nice balance between customization, nutrient levels, affordability and ease of use.

Fluval Stratum Reviews and User Experiences

Fluval Stratum has earned generally very positive reviews and experiences among planted tank owners:

The Good

  • Plants establish quickly and grow steadily when rooted in Fluval Stratum. Many report thick carpets of foreground plants filling in within weeks.
  • The rich black coloration creates an instantly beautiful aquascape look straight out of the bag.
  • Softened, acidic water parameters manifest as expected for most users with pH in the 6.5-7.0 range.
  • Strong root growth observed even in heavy feeders like Amazon swords or crypts. Much better than plain gravel or sand.
  • Nutrient levels seem to last at least 12 months before any drops in plant growth are noticed for low to moderate plant loads.

Potential Issues

  • Lightweight nature of Fluval Stratum grains makes it possible for unattatched stems to uproot when first planted. Using a deeper substrate layer helps weigh it down.
  • Ammonia spikes are common in the first 2-4 weeks as the substrate releases organics. Patience is required when first setting up a tank with Fluval Stratum.
  • Some aquarists report difficulties with rinsing dust out effectively before adding it to the tank. Taking the time to rinse thoroughly is recommended.

The Bottom Line

Fluval Stratum clearly provides significant benefits to planted tank aquascapes and plant health compared toplain gravel or other inert substrates. It delivers on its promises as an all-in-one plant substrate overall. Just be prepared for some initial ammonia spikes and take care when first planting.

FAQ About Fluval Stratum

Here are answers to some frequently asked questions about Fluval Stratum:

Can you use Fluval Stratum in a goldfish tank?

Yes, Fluval Stratum can be used when keeping live plants in a goldfish tank. The main downside is goldfish often dig and uproot plants. Using hardy, rooted plants is best. Fancy goldfish types are less likely to disrupt the substrate.

How long does Fluval Stratum last before needing fertlizer?

Expect 1-2 years of growth before signs of nutrient depletion are noticed in most cases. High plant mass tanks or very heavy root feeder plants may show deficiency sooner. Adding root tabs around heavy feeders can extend longevity.

Is it okay to mix Fluval Stratum with other substrates?

Fluval Stratum can be combined with other inert substrates like ecocomplete or ADA powersand. However, this may dilute some of its pH lowering capacity. Mixing with contrioil or aquasoil is not recommended.

How long does the ammonia leaching phase last?

Initial ammonia spikes when first submerged typically last 4-6 weeks. Monitoring parameters and water changes helps clear this organic phase safely. After a couple months, levels stabilize.

Can you use Fluval Stratum for non-planted tanks?

Fluval Stratum is specifically formulated for planted setups. While it could technically be used in non-planted tanks, it would be an unnecessary expense since its benefits are geared for plants.

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