In the studies with the freshwater organisms, the water hardness for five of the six laboratories ranged between 36 and 75 mg/L.
Freshwater organisms do not survive well in extremely hard water.
mnli hypothesis: Freshwater organisms do not survive well in extremely hard water. premise: In the studies with the freshwater organisms, the water hardness for five of the six laboratories ranged between 36 and 75 mg/L.