of the two i would go for the Flourish i feel thay last longer and the ratio of elements is a bit different (more iron and some other elements). personally i would skip over both of them and go for these, you get alot more for what you pay for.
go for flourish then. if anything you can break one tab into 2-3 pieces and spread that out. Remember that with root tabs + having a newly set up tank, you can get green water.
For that price, I might as well give it a shot! I mean, I'm paying $10 for 10 Flourish tabs every month, when I could spend $20 to get 50 tabs here that should last me a few months. Seems like it's worth a try, no?
I use the Flourish. They recommend replacing them every three months and that seems about right. The API is supposed to be replaced every month I think.