Couple weeks ago or so I got a shipment or elodea plants that may have frozen in shipment. I had to toss several. I put the remainder in a 10g tank with with an Aquatic Life T5 HO hood 2x 18w bulbs. The plant is not recovering for the most part.. the narrow elodea is dropping leaves like crazy and creating quite a mess in my tank. The thicker type is turning brown and looking melty, but it has new growth which looks healthy. I'm giving it about 8 hours light a day. Help?