A pool cleaning robot is designed to remove debris and dirt on a regular basis, not to clean a pool that has been neglected for an extended period of time.
If your pool is very dirty, it's important to first use a manual pool vacuum or skimmer to remove as much debris as possible before using a pool cleaning robot. Additionally, you may need to use other cleaning methods like acid washing, chlorine washing, or drain and cleaning the pool to get it back to a usable condition.
When the pool is in a usable condition, you can start using the pool cleaning robot to maintain it. Remember that pool cleaning robots work best when they are used regularly, so it's important to keep up with regular maintenance and cleaning of your pool.
It's important to note that a pool that has been neglected for an extended period of time may have other problems such as algae, bacteria, and chemical imbalances. These problems can not be solved by a pool cleaning robot alone, and it's best to consult with a professional pool service or pool equipment supplier to get a personalized solution.