I have a king bed that is peaking or bowing in the middle. I sleep on both edges so the middle is starting to peak up. It is a pillow top so we can’t flip the mattress over and it can’t be turned sideways because the mattress is not square. Any ideas on how to fix it, please share with me.
Unfortunately this is one of the side effects of the type of mattress you have and the materials it uses. Thicker layers of lower quality polyfoam in the pillowtop of a one sided mattress will usually develop these issues either from foam shifting or foam breakdown.
The only “fix” is to open up your mattress and either stretch the foam back into place or remove it completely if the foam has softened or broken down and replace it with better foam. You can do this yourself or have a local manufacturer rebuild your mattress if they offer this service. The innersprings or support layer is more than likely still fine.
Sometimes this can also be caused by the condition of the innerspring or support system under the mattress if it is sagging on one or both sides but firm in the middle (especially if it is a split king size where the edges of the foundation or innerspring are firmer where they meet in the middle than each side). You could test this by tryng your mattress on the floor to see if it makes any difference.
If the sags are more than the warranty exclusion when you are not on the mattress you may qualify for a warranty exchange if there are no other exclusions that may nullify your warranty (such as a small stain or damage that isn’t warranty covered). In most cases the sag needs to be more than 1.5" with no weight on the mattress but in some cases the exclusion is more. (and with premium foams it is sometimes less).
Other than this … you may need to replace the mattress if the hills and valleys are affecting your sleep.
Sometimes the “best” that can often come of this is to make sure that you don’t buy another mattress again with the same “weak link” in the mattress when you replace this one.