Israel use metric system i presume , just like in Europe .Ask for 0.3 to 0.8 mm grain size of PFS sand .
Finer would dust and can be easily siphoned out , and coarser will let debris collect in it so this size is a sweet spot that we ussualy use for discus .
Ask for Quartz , Silica based (Sio2 ) sand because they are chemically inert .