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SESK: Stuff Everyone Should Know · sesk.info/fish-ph-measure

What does aquarium pH measure?

How acidic or alkaline the water is.

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  1. How warm the water is
  2. How acidic or alkaline the water is ✔
  3. How much oxygen is present

Why: pH is a scale from 0 to 14. Values below 7 are acidic, 7 is neutral, and above 7 are alkaline.

Huh, didn't know that: pH is logarithmic, so small number changes are large chemical changes.

The dad joke
What did one pH paper say to the other? Stop being so basic.
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References

Answer: How acidic or alkaline the water is. pH is a scale from 0 to 14. Values below 7 are acidic, 7 is neutral, and above 7 are alkaline.

  1. USGS Water Science School: pH and Water www.usgs.gov/special-topics/water-science-school/science/ph-and-water
    The range goes from 0 to 14, with 7 being neutral.
    Checked 2026-10-11.
  2. USGS Water Science School: pH and Water www.usgs.gov/special-topics/water-science-school/science/ph-and-water
    Each number represents a 10-fold change in the acidity/basicness of the water.
    Checked 2026-10-11.

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