As all my nitrate filters have super-sized I have had to remove the original cartridge filter which after a few months is starting to block water flow. In the photo below you can see my $70 CL 100 acrylic tank's nitrate cart filter inundated with roots and dirt. So like all my other nitrate filters with carts it is time to lend relief to water flow by trimming off the old blue-bond fabric with scissors and just use the grate alone give roots something to grow on while good GPH water flow is restored. The roots will now act as both nitrate and mechanical filter. As you can see the root system is very healthy due to GPH concentrated water flow over the roots from all areas of the tank 48 tank turn-overs per day bringing the nutrients (Nitrates) to the plant, rather then a floating plant waiting for nutrients.
Flow restored
Flow restored