If you keep or are considering ornamental shrimp, you’ll quickly run into two abbreviations: GH and KH. Understanding what they actually measure – and why shrimp care about them more than most fish do – will save you a lot of confused troubleshooting later.
What GH measures
General Hardness (GH) measures the concentration of dissolved calcium and magnesium in your water. Shrimp use these minerals directly for healthy shell development during moulting, making GH one of the most important parameters for shrimp keeping specifically – too low, and shrimp can struggle to moult successfully; the ideal range varies by species.
What KH measures
Carbonate Hardness (KH) measures your water’s buffering capacity – its ability to resist sudden pH swings. A very low KH means your pH can crash suddenly with even small changes in the tank, which is far more dangerous to shrimp than a stable pH that’s simply not “ideal” on paper.
Why stability matters more than the exact number
Many shrimp species are more sensitive to sudden swings in GH/KH than to being slightly outside their preferred range consistently. This is why experienced shrimp keepers emphasise stable, gradual water changes over chasing an exact “perfect” number.
Adjusting GH and KH
Remineralising products exist specifically to raise GH/KH to shrimp-appropriate levels, particularly important if your tap water or RO/RO-DI water starts very soft. Active substrates can also influence these parameters, generally buffering toward a lower pH – research whether this suits the specific shrimp species you’re keeping before choosing one.
Testing and supplies
A dedicated GH/KH test kit is a worthwhile investment for any serious shrimp keeper – browse options in our Tests-Meters section, along with substrates in our Substrates section on The Aviary Hub.
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