what is that small square white rock thing call? i think it can keep good bacteria?

[Nuttawet]

what is seachem, what does it looks like and what does it do?

 

[Essjay]

Seachem is not a thing. Seachem is a company which makes a lot of different aquarium products.

 

[GaryE]

The best strategy is once you have a name for something, google it.

Seachem is a large, important company in the US and Canada - probably in Europe too. You probably have access to just as good products from their Asian competitors.

 

[Essjay]

This is Seachem

Seachem Laboratories

www.seachem.com