I have a group of ghost shrimp, and they have seemed to stop molting. When I first bought them, I would frequently see molt shells in the tank, but after a few weeks, they seemed to have completely stopped molting.
They would start to turn white until they are totaly opaque, and one of them seems to have died a rather slow and painful death today

Nitrates, nitrites, ammonia are at normal levels. My testing kit indicates that my water is extremely hard, and my pH is 8.4 or higher. I have no plants, and the ghost shrimp are in a tank to themselves. I feed them once a day with a pinch of crushed up fish flakes. The tank is 10 gallons with a sponge filter.
I have tried to add a drop of dilute iodine solution, but it doesn't seem to help.
