Pool noob here. First time post. Recently purchased a house with an in-ground pool and have been slowly getting up to speed. Pool has been great thus far but I woke up this morning to find the water levels lower by quite a few inches. I looked by the filter (Hayward, not sure of the exact model) and found that one of the PVC pipes is disconnected (see photos). Thoughts on how to reattach the pipe and fix the issue? Also, once attached, what needs to be done to make sure the filter is secure and working properly (that there are no air bubbles or debris which would impact performance and/or harm the filter)? Thanks in advance for all suggestions and guidance.