I want to get some root tabs for the Crypts in my 55. I was looking at RootMedic's site and am not sure if I should get the RootMedic Plus or the Plus Iron (don't remember the exact name) I am thinking that the one with iron is probably best for plants like swords, etc. and that the plus would be OK for my needs. But, I wanted to get some opinions from you guys. I am also considering making some diy tabs using Osmocote Plus. I know it would be a lot cheaper, but also more work. How do they compare to RM in terms of effectiveness and longevity?