Quartz sand is well calcinated, to remove traffic jam, you need to chemically destroy “these connections”. At the end of cleaning the tank, fill the filter with fresh quartz sand. It is better to use quartz sand of at least two fractions (better than neighboring ones, for example, 0.5-1.2 mm and 0.4-0.8 mm). Before filling with sand, put water into the tank, this will save the surface of the tank from unnecessary deformations. Do not forget that after filling the tank with quartz sand, first the filter must be turned on in the cleaning mode for 5 minutes. This will allow you to remove small fractions from the sandy filter and “denser” to lay the filter material.