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    Illustration of green water

    Decrease in dissolved oxygen & hypoxia

    decrease in dissolved oxygen; hypoxia 1 1

    What you see

    The signs of hypoxia (lack of oxygen) are characteristic and often alarming:

    • Fish gather at the surface with their mouths open, trying to take in oxygen from the air, especially in the early morning (a phenomenon known as gill-gasping).
    • Wildlife congregates in large numbers around areas with moving water, such as waterfalls, water inlets, and fountains.
    • The fish become unusually sluggish, stop feeding, and don’t swim away when you approach.
    • Sudden deaths occur, often affecting the largest specimens first, as they have higher oxygen requirements.
    • The water is thermally stratified: the surface is warm, while the bottom is cold and completely devoid of oxygen.

    What this means

    Your body of water is in a state of hypoxia: its respiratory balance is deficient. In concrete terms, oxygen consumption by living organisms exceeds the natural production capacity of the environment.

    Three major factors combine to explain this critical imbalance:

    1. High Temperature (Physical Law): This is an immutable law. The hotter the water, the less dissolved oxygen it can hold. During the summer, your pond's storage capacity mechanically decreases, even as the fish's needs increase with the heat.
    2. The Nocturnal Respiration Trap: At night, the chemistry reverses. While algae and plants produce oxygen during the day through photosynthesis, they become consumers at night to ensure their own respiration. In an algae-rich pond, this nocturnal consumption is massive. It depletes the reserves accumulated the previous day, causing a sharp drop in oxygen levels just before sunrise. It is at this precise time that the majority of deaths occur.
    3. Excessive Organic Load: The presence of mud, dead leaves, or decaying algae fuels intense bacterial activity at the bottom of the water. This decomposition bacterial activity is extremely oxygen-hungry. This is referred to as an explosion in Biochemical Oxygen Demand (BOD). Bacteria "pump" all available oxygen to digest the mud, inevitably leading to anoxia at the bottom, putrid fermentation, and the production of toxic gases.
    decrease in dissolved oxygen; hypoxia 2 1

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    Why act now?

    Hypoxia doesn’t just affect the few fish visible at the surface. It’s a sign that the ecosystem is entering a critical state:

    • During heat waves or thunderstorms, oxygen levels can drop to zero within a few hours, wiping out the entire fish stock.
    • Without oxygen, the substrate undergoes putrefactive fermentation, producing toxic gases (H₂S, ammonia) that accelerate the degradation of the environment.
    • Noble species (predators: pike, walleye, salmonids) have the highest oxygen requirements. They are the first to disappear, making way for more resilient but invasive species that disrupt the food chain.

    The TASO Solution
    Deep Oxygenation & Demand Reduction

    Simply spraying water on the surface is ineffective because it doesn’t treat the root cause. TASO treats the entire water column to address the cause, not just the symptom.

    1

    Deep Mechanical Oxygenation (Physical Action)

    We install bottom aerators that inject air directly into the deeper layers. This allows for complete destratification (mixing of the water layers) and temperature homogenization. Oxygen is then available from the bottom to the surface.

    2

    Reduction of Biological Demand (Biological Action)

    To improve water quality in the pond, we introduce specific bacteria that accelerate the breakdown of sediment and organic debris. Less organic matter to break down means the system consumes less oxygen, leaving more oxygen available for the fish.

    3

    Soil Stabilization (Mineral Action)

    Adding carbonates increases the sediment’s redox potential (oxidizing power), thereby limiting oxygen-consuming fermentation.

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    Products
    & Related Solutions

    To restore oxygen levels in your body of water:

    oxylake

    Oxylake

    Oxygenation solutions for ponds and bodies of water
    Learn more
    AQUASUB

    AQUASUB

    The intensive mixing hydro-ejector
    Learn more
    calix

    Floating fountain

    Visual stimulation & natural oxygenation
    Learn more
    nautex

    Nautex

    the standard mineral treatment for all bodies of water
    Learn more

    Need a study?

    Each protocol is tailored to the initial assessment, the characteristics of the body of water, and its intended uses.

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