Charles wrote:

And after 3-4 weeks it releases all the things it caught... i dont use
it. Manufacturers love it because its a high margin item and you have
to buy lots of it to effectively use it.

I use it in my Top Fin HOB filter. The media refills come with the sponge
thing and a carbon packet. I change those things about every 4 weeks. Do
you think it would be a good idea to stop using the carbon and save it
until I need it for disease control, cycling other tanks, etc? Or, should
I just use it because it's there? What you have said has made me rethink
always putting it in my filter.