Improving the filtering effect
The retaining capacity of your filter unit is given by the size of silica sand grains, used in the filter.
Replace sand with Zelbrite filtration medium, which has several times greater surface area of grains and can capture finer particles. It also captures nitrates contained in the water. It will save you resources and improve the purity of water.
More tips for better pool maintenance
It is a pool edge finished with overflow channels (typical for public swimming pools) which carries water through retention reservoir to the filtration circuit.
All fields have to be filled.