Clear the edges of the hole, remove the contamination that prevents adhesion of the material to the surface. If the water pressure is high, it is necessary to put a cloth, wood, or other plug into the hole, which must be preliminarily deepened by 1-2 cm.
(only in case of elimination of an active leak)
Pour the dry mix into your hand (the use of gloves is mandatory!), attached to the place of leaking, and hold for 5-10 minutes while pressing and simultaneously rubbing the material into the hole. After solidification of the mortar, it is necessary to clear dry powder from the edges.
Add clean water into the tank with the dry mix at the ratio of 150 ml of water per 500 g of the dry mix and stir until a homogeneous mass is obtained. The mortar must be used within 1.5-5 minutes from the moment of pre-mixing with water. Form a seal from the prepared mortar in accordance with the shape of the holes, press the seal to the place of leakage, and hold under strong pressure for 5-10 minutes. Then, remove the excess material. After the elimination of the leak, apply a waterproofing layer.