After making countless batches of tea over the years, this is what I have learnt about achieving that elusive pink color. Make sure to aerate the tea properly and use ice cold water. You will know you are on the right track when the concentrate takes on a reddish hue. If the concentrate is still brown, you can try adding more baking soda. But be careful not to add too much because otherwise it will turn the tea bitter. If the tea still doesn’t turn pink, then use another brand of tea. Some brands are better quality than others. Also check how fresh the tea leaves are. I have realized that I am able to more easily achieve the pink color when the leaves are fresh. They  have a delicate floral aroma to them.