Juwel Nitrate Removal Sponges...

[chrismr]

Do they actually remove nitrates, or is this just a way they try and make you spend more money?

 

[Bloo]

Well yes, they do remove Nitrates. A recognised brand like that won't dare to make a product that doesn't work.

However..... it's a waste of money. Just stick to your weekly water changes - that's much better (for your pocket and the fish).

 

[jarmado]

i tried opening one of their compact nitrate sponge and there is a capsule of black/grey bits inside.
probably bacteria that should consume the nitrates when released to the sponge/water.