What are foam blocks for and why to BAO sumps not include them?

Foam blocks are not something you will find in any BAO custom sump or any of our standard line sumps.  When discussing custom sump design with customers we sometimes get the question of why they are not utilized, as they are accustomed to having them in their existing sump.

For starters what is a foam block?

Foam blocks in general are a large pore sponge used in between the skimmer section and return.  These are often used to prevent bubbles from entering the return can creating micro bubbles in your display.  To a lesser degree they are used for mechanical filtration.

So why do BAO sumps not include foam blocks?

Our sumps are designed to trap bubbles via a bubble trap instead of a foam block.  If designed properly a bubble trap is just as effective as a foam block at preventing micro bubbles in the display.  The catch is using a baffle system to trap bubble requires more effort and knowledge of placement than randomly throwing in a foam block. 

We also try and design our sumps to keep needed maintenance to a minimum.  Foam block tend to accumulate detritus and need to be cleaned frequently (at least twice a week).  Being that they are a porous sponge, over the long term they become harder and harder to clean and often end up leaching nitrates back into the tank.

As mechanical filtration, we find that foam blocks are often placed poorly. We find that mechanical filtration is best placed prior to the skimmer to allow removal of any larger particles.  This allows the skimmer to work more efficiently to remove the remaining organics in the water.   You will notice, however, that foam blocks are almost always placed after the skimmer.


So ditch the foam block and opt for a sump that has been designed correctly.  If you have any design questions we are always happy to chat.  With over a decade of experience we know what works and what is just marketing.