From https://www.swimmingpoolsteve.com/pages/chemistry.html this video explores why the term "shocking" is often poorly applied to swimming pools and can lead to an incorrect understanding of the fundamental chemical process for pool maintenance. Shocking often refers to adding chlorine to your pool, or perhaps adding a non chlorine based oxidizer "shock" product, but in reality there is better terminology which could be employed to be more clear about what you are doing (or what you need to do) to the pool. Breakpoint chlorination - This is where you increase the free chlorine level to be 10 times the combined chlorine level and then hold it at this elevated free chlorine level for an extended period of time. This is a process which all pools need to do when the combined chlorine levels grow, and often people refer to this process as shocking, or super chlorinating. Non-oxidizer shock - Oxidizer like potassium monopersulfate can be used as a pool shock. This helps to break down and oxidize organic contaminants in the pool quickly, and leaving the water safe for swimming within just a short period of time. Raising chlorine levels - If you were to add chlorine to your pool and then refer to this process as shocking the pool, you would not be totally incorrect, however this terminology would leave the door open to misinterpretation by anyone you are speaking to about your pool. Instead of saying you shocked the pool, you would simply say that you added some chlorine or raised your free chlorine level. ... https://www.youtube.com/watch?v=Y2Isf0cCxqk

From http://swimmingpoolsteve.com/pages/installation-tips.html this video reviews a pool equipment installation where the pump has a serious suction side flow restriction and the polaris pressure side pool cleaner line is kinked ... https://www.youtube.com/watch?v=8qf9tq2BWGk