Be very carfull when first planting sea grass in the aquarium. Never push them into the sand, rather, dig a small hole in the sand and place the roots into the hole. You may need to prune the grass of dead or dying leaves to prevent it from decomposing and fowling the water. At first, the leaves of the grass dyed off, but withing a few weeks, new growth was evident. I would think that this was a normal occurance. Im sure that the plant did not want to waste energy on trying to save the existing leaves, but rather just grow new ones.