Purigen Filtration Bags
 

A guy at a LFS convinced me to buy some of this for my box fuge in my nano along with the carbon

Im wondering if this stuff is worth while or not.

It also says to use 100 ml bag i bought with 100gallon tanks. Would using this on a 28 be to much, and harm the tank?

No
 

Purigen works very similar to carbon but it claims to have absorbant properties 500% greater than its black counter part. I personally love most of the Seachem products and purigen is no exception. You do not have to worry about over filtration. No such thing as to little nitrates.
Levi

Just remember that certain things can cause purigen to become toxic, when regenerating it.

http://www.seachem.com/support/forum...=purigen+toxic