Creating a Lush 25-Liter Walstad Tank: A Step-by-Step Guide

Dive into the world of low-tech planted tanks with this easy guide to setting up a thriving 25-liter (approximately 6.6 gallon) Walstad aquarium. The Walstad Method embraces natural processes, using a soil-based substrate to provide nutrients for lush plant growth. This approach creates a self-sustaining ecosystem that requires minimal maintenance while offering a beautiful aquascape.

Gathering Your Supplies: Substrate and More

Organic Potting Soil: The foundation of your Walstad tank, you’ll need about 1 liter (2.1 lbs. / 1KG) of organic potting soil for a 1-inch layer. Make sure it’s free of pesticides, herbicides, and added fertilizers.

Sand: A 2-inch layer of coarse-grained sand, totaling around 2 liters (4.2 lbs. / 2KG), acts as a cap to prevent soil from clouding the water. Black Diamond blasting sand is a good choice.

Dechlorinated Water: Essential for the well-being of your aquatic life.

Building Your Underwater World: Step by Step

Prepare the Soil: Sift the potting soil using a colander to remove large debris, twigs, and rocks

Layer the Substrate: Create a 1-inch layer of prepared potting soil at the bottom of your tank, spreading it evenly.

Cap with Sand: Gently add the 2-inch layer of sand on top of the soil. This cap is crucial for preventing a messy and potentially harmful release of soil nutrients into the water column.

Gentle Water Filling: Slowly pour dechlorinated water onto a plate or cardboard placed on the sand to minimize substrate disturbance.

Plant Power: Introduce a diverse range of plants, with an emphasis on fast-growing stem plants known for their ability to root easily. Stem plants like Hygrophila polysperma, Ludwigia repens, Rotala rotundifolia, and Bacopa caroliniana are excellent choices. Refer to the plant list below for more ideas!

Floating Plant Advantage: Add floating plants like Salvinia, red root floaters, or Limnobium laevigatum. These powerhouses of nutrient absorption also provide shelter and enhance the natural look of your tank.

Patience for Cycling: Let the tank cycle for a minimum of two months before adding fish or shrimp. This crucial waiting period allows beneficial bacteria colonies to establish, breaking down harmful ammonia into less toxic nitrites and then nitrates. It also gives the initial ammonia spike from the soil time to subside.

Stocking Your 25-Liter Walstad Paradise

Fish (Select one combination):

Clean-Up Crew:

• Shrimp: 10-15 Red Cherry Shrimp will be your dedicated algae-eating team, keeping the tank tidy and adding a splash of color.
• Snails: Algae Control and More: A small number of Malaysian Trumpet Snails or bladder snails contribute to algae control and break down organic debris.

Plant Variety for a Thriving Ecosystem:

• Fast-growing stem plants: Hygrophila polysperma (Dwarf Hygro), Ludwigia repens, Rotala Rotundifolia (Dwarf Rotala), Bacopa caroliniana, Java Moss (Christmas moss), Hornwort (Ceratophyllum).
• Floating plants: Salvinia (Watermosses), Limnobium laevigatum (Amazon Frogbit), Phyllanthus fluitans (Red root floaters).
• Other suitable options: Cryptocoryne wendtii, Anubias nana (Anubias barteri / Dwarf Anubias), Java fern, Water Sprite.

Important Considerations for Plant Selection:

Aggressive Growers Are Key: In a new Walstad tank, especially, choose plants that are known to be fast and aggressive growers. They will outcompete algae for nutrients during the initial setup phase.

Light and CO2 Needs: Opt for low-light plants that don’t require supplemental CO2, as these are best suited for the Walstad Method.

Maintaining Your Low-Tech Gem

Lights this is main element that effect the Dirt Tank: When using LED lights for your 25-liter dirt tank, a general guideline is to provide a photoperiod of at least 12 hours per day. This duration aligns with the natural daylight hours that aquatic plants receive in their native habitats but Research has shown that some plants, like Hydrilla, exhibit significantly faster growth when exposed to 12 hours of light compared to 10 hours.

However, the sources emphasize that it’s important to consider the intensity of LED lights. While a 12-hour photoperiod may be suitable, constantly exposing your plants to the intense illumination of LEDs can be detrimental2. In natural environments, light intensity fluctuates throughout the day, with peaks at midday and gradual reductions in the morning and evening. A continuous 12-hour exposure to strong LED light doesn’t replicate these natural variations2.

To address this and provide a more natural lighting cycle, the sources strongly recommend implementing a “Siesta Regimen.” This involves incorporating a 2–4-hour dark period in the middle of the day3. This midday break simulates the temporary shading that occurs in nature due to clouds or trees.

In my Tank, the lights are on 3Hrs in the Morning after 1 hours of sunrise and again 3hrs in the evening, the lights come on 1 hour before sunset.

The benefits of the Siesta Regimen include:

• Algae Control: Algae often thrive in conditions where CO2 becomes depleted due to prolonged, intense photosynthesis by plants4. The siesta allows CO2 levels to replenish, reducing the competitive advantage algae may have in the afternoon.
• Tank Overheating: Continuous lighting can contribute to excessive heat buildup in the tank. A midday break helps regulate temperature.
• Reduced Photorespiration: In high light and low CO2 conditions, plants can undergo photorespiration, a process that hinders growth. A siesta allows CO2 levels to recover, minimizing this issue.
  • The sources observed that CO2 levels rebounded significantly during a midday siesta in their tanks6. They attribute this recovery to a combination of factors, including:
  • Reduced CO2 consumption by plants during the dark period
  • Increased CO2 production from bacterial decomposition, which is stimulated by the oxygenation of the water resulting from morning photosynthesis
• By implementing a Siesta Regimen with your LED lights, you can create a more balanced and natural lighting environment that promotes healthy plant growth while minimizing algae issues. Remember to observe your plants and adjust the photoperiod as needed.

Water Changes: Top-offs are generally sufficient for a well-balanced Walstad tank. However, you can perform small, 10-20% water changes every few weeks to maintain optimal water quality if necessary.

Plant Trimming: Trim fast-growing plants as needed to prevent overcrowding and maintain a pleasing aquascape.

Filtration: Often Optional: Filtration is typically not required in a Walstad tank due to the natural filtration provided by the plants and substrate. If you do use a filter, choose a gentle sponge or hang on back filter for circulation and oxygenation without disturbing the soil layer.

Key Takeaways for Walstad Success

Research: Always research the specific needs of your chosen fish, shrimp, and plants to ensure compatibility.

Start Small: Begin with a lower number of livestock and gradually increase the population while monitoring water parameters.

Patience: Give your dirt tank ecosystem time to establish itself. A balanced Walstad tank can provide years of enjoyment with minimal intervention.

Embrace the beauty of a naturally balanced aquarium with your 25-liter Walstad tank! By following this guide and allowing nature to take its course, you’ll create a stunning and thriving ecosystem that rewards you with minimal maintenance and maximum visual appeal.

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