[Peter Finke]

That is a good instrument for a Paro friend. I measures in mg/cm (milligram pro centimeter). It’s the sum of all minerals dissolved in the water, yes, another wy of measuring but the same thing than waht you control with electric conductivity. Pure water (H 2 O) ist zero mg/cm. The original Paro-waters are between 7 (!) and 30 mostly, for aquarium usages we recommend 10 to 80. I try to keep it around 20 or 30 mostly. Then you will have no problems with the eggs staying adhesive when the male tries to fix them on the ceiling of the cave. With time, the value rises, but with the water changes (using destilled or osmosis water) you can reduce it again.