Plaster pool walls will expand and contract as the ground settles and shifts. Over the course of time, the plaster will lose elasticity and cracks will form. In most cases, these cracks are minor and can be repaired. It is important to lower the water level below the cracks to make it easy to repair them.
You can purchase pool plaster mix and use it to completely fill the cracks before drying with an air gun. If the cracks are very large, they could signal a structural problem, which means you need the assistance of a professional before the cracks completely destroy your pool.
While the majority of pool problems can be easily fixed or even prevented with regular maintenance, you should never try to perform advanced repairs; this is especially the case when it comes to structural or electrical issues. Instead, get in touch with an expert pool repair team.