For underwater joints certain prerequisites must be met to ensure optimum adhesion: The joint width should preferably be 10 – 15 mm and joint depth should be limited to approximately 8 – 10 mm by backfilling material.
Prior to sealing, the sides of the joints must be thoroughly cleaned of loose and dusty particles, residual mortar and contamination from oily or greasy substances. The sides of the joints must also be dry because a film of moisture on the surface will act like a release agent. The joint edges should be masked. Mineral, absorbent joint sides should be treated with OTTO Primer 1218, applied undiluted to the sides, using a paintbrush. After airing the primer and injecting OTTOSEAL® S 18, the sealant must be smoothed within approx. 6 minutes before a skin starts to form, using a tool moistened with OTTO smoothing agent. Ideally, the pool should not be (re)filled until two weeks after the joints have been sealed with OTTOSEAL® S 18. After the sealant has cured completely and the pool is filled with water for the first time it should be chlorinated immediately with a 2 mg/l intermittent chlorination during the first 2 days. During this time the pH value should be adjusted to between 7.0 and 7.2 to achieve the highest possible effect of the disinfectant. For operation thereafter the concentration of free chlorine should be 0.3 – 0.6 mg/ litre (warm water whirlpool 0.7 – 1.0 mg/litre) and the pH value between 6.5 and 7.6 (ideally 7.0 – 7.2). The water circulation should be adjusted so that the water constantly runs over the overflow edge of the pool. Alternative methods, such as UV radiation or ozonisation do not have sufficient sustained-release-effect to prevent a fungus attack.