I'm gathering info for a 75 gallon display with a 40 gallon sump. A coast-to-coast setup appears to be the least visually intrusive, and continually skims the entire surface for efficiency. The Bean-Animal appears to be the best choice for a silent system and max protection against overflow.

So far I have not found any info regarding the required size/volume of the internal box. Some setups combine an external box with the internal box. Is this done to increase the total volume of water yet minimize the size of the internal tank?

Thanks for any info,

Tom