I will soon be repurposing my cycled 10 gallon tank to start a red cherry shrimp colony. My pH is approximately 7.6 but my kH is only around 4. Do I need to boost kH or can I the shrimp get enough calcium from supplements and/or calcium rich food? Also, I have heard that black gravel is less stressful for the shrimp, so is it a good idea to replace my whitish tan gravel for better results? Thoughts are much appreciated as I am looking very forward to starting my new shrimp colony.