Sealing the exterior of cracks is done with Epoxy Gel type Bonder. Testing The System Test cracks that are ill defined, or if dust or debris is in the crack. This testing is done by injecting water into the crack area. Water left in the cracks will not effect the injection process or the curing of the Epoxy Systems' Injection Resin. Heavier injection resin forces the water out the cracks.
Water injection helps clean the cracked areas.
More important, is that it helps avoid the unexpected. This process of flushing the cracks is commonly skipped by more experience contractors, who can tell if there will be a flow of resin, by just looking at them. However, when in doubt water testing is a must. If the cracks contain algae, chlorinated water containing copper sulfate is injected. After pumping this mixture is left over night.