Large Bio rocks in sump

[mr9iron]

I was reading a while back about a very porous rock, almost cinderblock like, that some were putting in their sumps to add biological filtration to their tank. I cannot remember for the life of me the name of these things. I would like to put a couple in the sump for a minimalist/semi bonsai tank I am building.

 

[Spinelessspade]

Marine pure blocks is what you are thinking of I beleive

 

[ridetheducati]

I was reading a while back about a very porous rock, almost cinderblock like, that some were putting in their sumps to add biological filtration to their tank. I cannot remember for the life of me the name of these things. I would like to put a couple in the sump for a minimalist/semi bonsai tank I am building.

Marinepure filter media.

 

[mr9iron]

Marine pure blocks is what you are thinking of I beleive

That's exactly what I was thinking of. I am thinking two of these in the sump should help quite a bit.