Calcium levels low in hard water

[Allybb]

Been keeping a 55 gallon planted aquarium for ages, and just decided to get serious with understanding my water parameters so that I can make it look spectacular rather than limping along. Whenever I've tried to keep ghost shrimp in the past, they live for a few weeks, seem happy, then one by one they die. I just bought an API calcium test kit - I never tested before because I have really hard well water (I thought). White marks around every faucet I have. I tested the water in the aquarium first, and it turned to the end color with the first drop. I then watched a youtube video to see how it was supposed to work - I had done it right... I then tested my tap water, and it came out 40 ppm - way lower than I expected. Could my hard water be mostly magnesium and very little calcium? My KH tests out at 54 (3 dKH) with an aquarium pharmaceuticals kit. Only have an Easy Strip for GH, and it reads 150. pH is 8 (yeesh). Two questions - 1. What am I not understanding about water hardness, my assumptions are blown. 2. If I already have really hard water, how can I dose calcium for the shrimp without wreaking havoc? Gonna give them some tums for the time being.

[Mustafa]

Don't worry about dosing anything. Your water seems fine. Just make sure that you tank has been cycling and maturing for at least 2 months. That's usually the biggest problem. Shrimp get calcium from their food.