We don't recommend Green to Clean. It is designed to kill algae when you have an extremely high CYA level. It works at doing that, but has various possible complications that make it anything but trouble free. Also, if you do have a high CYA level, it is far better to lower the CYA level, which will just cause further problems, rather than bothering with special products that cost extra. Assuming your CYA level is reasonable, there are much simpler ways to kill algae than using Green To Clean.
There are various brands of wood fiber based DE substitutes. They work well for the most part. Some people say that they don't backwash as well, others that they backwash better than DE. Just about everyone agrees that they filter just as well.