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    Illustration of green water

    pH fluctuations & chemical instability

    Understanding the causes of fluctuations
    and achieving long-term water balance

    pH fluctuations, chemical instability 1 1

    What you see

    Unlike green water, this imbalance is often invisible to the naked eye, but measurements and observation of the environment don’t lie, so:

    • The pH level is unstable. It is low in the early morning (tending toward acidic) and spikes in the late afternoon (alkaline, sometimes exceeding 9 or 10).
    • The fish are agitated, jumping out of the water, rubbing against the bottom, or gasping for air at the surface.
    • A whitish, rough crust forms on the leaves of aquatic plants or on the walls of the pond.
    • The water may remain crystal-clear, but its chemical properties have become unstable and dangerous to living organisms.

    What this means

    These fluctuations indicate insufficient buffering capacity (TAC/KH ratio too low).
    The water lacks carbonates capable of absorbing fluctuations in acidity.

    The cause is natural but exacerbated by a lack of minerals:

    • During the Day: Photosynthesis consumes CO₂ (acid), causing the pH to rise naturally.
    • At Night: Breathing releases CO₂, causing the pH to drop.

    The Biogenic Decalcification Phenomenon: The white deposits you see are a sign that the plants are lacking carbon.

    Since there is no free CO₂ in the water, they are forced to break down bicarbonate molecules to extract carbon, causing calcium (lime) to precipitate on their leaves.

    pH fluctuations, chemical instability 2 1

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    Why act now?

    Prolonged chemical instability is unacceptable for aquatic life. The biological consequences are severe:

    • Ammonia Toxicity (The Silent Killer): This is the number one danger. Below a pH of 8, ammonia exists in the form of ammonium (NH₄⁺), which is relatively non-toxic. But as soon as the pH exceeds 8.5, it turns into ammonia (NH₃), a gas that is deadly to fish.
    • Destruction of the Mucus Layer: Constant fluctuations in acidity attack the fish’s protective mucus layer, opening the door to parasites and bacterial infections.
    • Interruption of Biological Filtration: The beneficial (nitrifying) bacteria stop working when the pH is unstable. The nitrogen cycle is disrupted.

    The TASO Solution
    Restore a durable mineral buffer

    Many people make the mistake of adding acid to lower the pH. This is a temporary solution that exacerbates instability in the medium term. The TASO approach does not involve forcing the pH, but rather locking in its stability. This is what is known as pH buffering.

    1

    Buff Power Adjustment (Mineral Action)

    We increase the carbonate hardness (TAC/KH) through targeted mineral supplementation. By increasing the “alkaline reserve,” we restore the water’s ability to withstand fluctuations in CO₂ without causing the pH to change. The water once again becomes a buffered and stable environment.

    2

    Biomass Regulation (Indirect Action)

    If the fluctuations are caused by excessive photosynthesis (too many algae or plants), we take action at the same time to reduce the plant biomass. Less photosynthesis means less CO₂ consumption, and therefore greater stability.

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    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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