I suggest to use Sikagard 62, as the client want to keep the water non-toxic, but may add chloride from time to time. Therefore Sika TopSeal 107 is not suitable.
Consumption Sikagard 62: 2 x 0.3 kg/m2
Remark: Depending on the actual concrete surface conditions (voids, blowholes, etc) Sikagard 75 EpoCem may need to be applied to close these holes.
(approx. consumption: 0.5-1 kg/m2)