BellaRay

I have had ghost shrimp for almost a week and one already died... I cycled it and used some water from my older fish tank (1.5 years). My other shrimp was eating him in the morning, but I thought it was a molt. The shrimp "molt" was cloudy white and I couldn't find him so I figured he was dead. The temperature is at 70 degrees F. I got testing kit to test the water... any advice?