***You can use either 1 or 2 SK5000 roller mats in these sumps. The flow rate into the sump will determine whether you need 1 or 2 roller mats. Each SK5000 is rated for 1200 GPH MAX, so 2 will be 2400 GPH MAX. If using only 1 Roller mat, you can use 1 filter sock as well. For the quietest operation we recommend keeping the flow below the SK5000's Maximum flow rate.