results

I use Fluorish as the only additive in my 30 gal low tech plant/fish tank. I saw a difference (new growth) within a couple of weeks on my slow growing Anubias and Crypts.
 
Depends on the size of the tank. They will positively affect any tank, but you'll notice more of a difference in a smaller tank.
Especially the Excel.

Len
 
AquariaCentral.com