Hi terry, I have the 406 on my 55 and this is my setup. Bottom basket I have Bio foam, in the next two baskets I have carbon and purigen alternating like a checker board, the top basket has my biomax covered with filter floss. This setup has been the best setup that I have tried by far and I have tried many, it has not affected my plants and my water is crystal clear. But I will say that I also run a sunsun HW 303b additionally.
"He who never made a mistake, never made a discovery".