bricks

Most of Felipe's tanks have these kinds of bricks in them - lots of holes and the perfect size for pikes, holding females, fry, etc. to hide. They'd be excellent for plecos, I think, as well. http://ehp.niehs.nih.gov/wp-content/uploads/2013/08/ehp.121-a242.g009.png Anyone know of a...

Hello just wondering it anyone knew if it was safe to but regular cinder blocks and bricks into a tank. I am thinking of using them for a new tank design.