Contact Nulantic is you are considering a retrofit or upgrade your pressure filter. We offer granular media filter parts that may improve your existing system with lower capital cost than a replacement. The MULTIWASH PRO trough can be added to most systems, solving media fouling and backwash problems featuring simultaneous air and water backwash while overflowing trough weirs to help prevent media loss during the backwash process. MULTIBLOCK Underdrains can be fitted with the unique Laser Shield™ media retaining system that eliminates the need for support gravel.