Official figures from the water utilities
Is your tap water suitable for shrimp?
A GH/KH test is still necessary — this tool does not replace it.
Your water
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No result? Just enter the hardness manually below.
This KH is based on an official Pidpa water composition sheet for this zone. It is a zone value, not your own aquarium measurement.
For Brussels, official Vivaqua values depend on the exact address. We therefore do not show a fixed value per municipality. Enter your own GH/KH test result for the most reliable advice.
Official data found, but this municipality has several drinking-water networks. Enter your own GH/KH test result for the most reliable advice.
Official data found, but in this municipality the hardness differs from street to street and the source has no supply zones. Enter your own GH/KH test result — or the value Gruppo CAP gives for your address — for the most reliable advice.
Official data found for one supply network in this municipality. We don't know whether your address is on this network, so we don't fill in a value — enter your own test result or your water supplier's value.
Official range for the whole municipality of Porto — not a value for your address. Enter your own test result for the most reliable advice.
°dKH
We didn't find official KH data for this zone. Enter your own KH drip-test result to calculate the expected pH in your aquarium.
Zone data gives an estimate; your drip test gives the real value for your aquarium.
Units and examples
Belgium, France and Italy measure in French degrees (°fH); the Netherlands and Germany in German degrees (°dH); Spain and Portugal usually in mg/L CaCO₃. The aquarium hobby always calculates in °dH. 1 °fH = 0.56 °dH = 10 mg/L CaCO₃
Don't use that water. A softener exchanges calcium and magnesium for sodium. Your GH drops toward zero, but the salt stays in the water. That's not soft water — it's water without the minerals your shrimp need to molt. Draw water from a tap before the softener, usually the outside tap or the one in the garage, or use reverse-osmosis water and minerals instead.
Your result
No value selected
Use your measurement to see the result.
Total hardness (GH)
Caridina · Bee, Crystal4–6 °dH
Neocaridina · Cherry, Blue Dream6–14 °dH
Ideal range Tolerance range
in your aquarium *
* The pH value is calculated for water that has been aerated for 24–48 hours, until gas equilibrium with the air is reached. In an established aquarium, the pH is usually lower: active substrate, driftwood, and the respiration of animals and bacteria continuously add CO2, which pushes the pH down. This value is therefore your starting point, not your final value.
Before you buy anything
- Water utilities publish GH, not KH. For Caridina, that carbonate hardness is exactly what matters. A GH/KH test is still necessary — this tool doesn't replace it.
- This figure is an average across an entire supply area, not a measurement at your own tap. Expect a deviation of a few degrees due to your home's plumbing and the season.
- Your water is very soft. Soft water dissolves copper and zinc from old pipes, and copper is deadly for shrimp. Let the tap run for a minute in the morning first, and test for copper.
