I need to fill the gap around the pool between its edge and the tiles, it is a joint 2-3 cm wide 1.5-2.5 cm deep (see photo). The existing cement filling crumbled after the first winter. I found on the web: http://www.hasoft.cz/specialni-maltoviny/opravy-a-prilnavost/spravbeton.php https://velkoobchod-eshop.cz/cementove-a-nivelacni-hmoty/17534-vyplnova- opravna-sterka-na-beton-quartz-dopln.html # / kusove_atributy-1_ks Do you have any personal experience, can you advise which variant I should use?