I have a uniquarium that is 40galon it has the compartments In the back for the filtration. it has compartments for bio balls and other types of filter. As I understand what bio balls do is add oxxigen to the water and produce good bacteria to kill amonia. I at ached a photo of the foam blocks we have at work. I was thinking of cuting them in squeres 2x2 and using that insted of the ball's. What do u all think? they have a hard coating but the Inside is softer and poris all the pices are identical. Any input on this would be awesome.