Hi Heatherly30,
Unfortunately you are experiencing the symptoms of a “typical” pillowtop which uses lower density polyfoam and thicker layers of fiber which will soften and compress. Unfortunately … this is fairly typical of major brand mattresses which often use lower quality materials even in their higher end mattresses. Smaller manufacturers tend to use much higher quality materials and sell them for much less but of course the “label” doesn’t have a heavily marketed name so many consumers are led to believe that these “off brands” are lower quality and value while in most cases the opposite is true.
King size mattresses have more of this problem because the area in the middle is much less used and will stay more lofted while the areas that are used … if they use thicker layers of fiber or lower quality foams … will compress more creating the hills and valleys that are so common. Higher quality materials and foams that are less subject to early softening and compression will help alleviate this. This is why it’s so importantto know the quality and density of all the layers in a mattress and of course the larger manufacturers are more focused on marketing stories than they are in providing meaningful information about what is actually in their mattress. The largest national brands are all best avoided if you are looking for higher quality and better durability in any particular budget range. This article will give you some guidelines that will help you avoid most of the worst choices when you are shopping for a new mattress.
As you have also discovered … a topper on a mattress that has softened will just follow the dips in the mattress and while it may offer some improvement for a while … it doesn’t solve the underlying problem.
With heavier weights … the durability of the materials in your mattress become especially important. This is especially true in the upper quilting and comfort layers whch are the “weak link” of most mattresses and soften and degrade the fastest. Most innersprings and support layers will long outlast the comfort layers in a mattress.
Memory foam can be attractive to many people but it is also a very “tricky” material to get right and it’s important to use high quality memory foam for durability. Memory foam is usually best used in fairly thin layers which can offset the risk of sinking in too far with the heavier parts of the body causing misalignment and possible back issues. It is also very soft (even though some types can feel firmer initially because they take “time” to get softer with body heat and seem firmer than they really are with movement). They are not supportive enough to be used in a support layer which is why all memory foam mattresses use a more supportive material in the support core(either high density polyfoam, an innerspring, or latex). You can see some of the different types of materials that are used in comfort layers here (for pressure relief and comfort) and support layers here (for support and alignment).
A more detailed article about memory foam is here and latex is here (another high quality specialty foam).
Before you consider the Lucid … I would read post #10 here. It is a poor choice for most people except as a temporary “throwaway” mattress but it would be an even worse choice for a couple that was heavier. The memory foam it uses is very low density/quality.
The Ultimate dreams is a completely different story. The manufacturer is a member of this site (meaning that forum members receive the shredded latex pillow with their purchase as a bonus if you let them know your username here) and uses very high quality materials including talalay latex in the comfort layers and high quality polyfoam as the support base. They also allow you to choose the firmness of the latex in the mattress. This is a very high quality and value choice.
There is always some risk however with an online purchase however (especially when there are no returns) because you aren’t able to test the mattress for PPP (Pressure relief, Posture and alignment, and your Preferences) before you buy it so some local testing to get a sense of the material and the firmness level that you may do best with is a good idea. It is also less risky to buy a mattress that you have personally tested and know “works” for your needs and preferences. While I would certainly pay a premium to some degree for a local purchase … if the “premium” for a similar local mattress is too big a difference then an online purchase can be very attractive even with the additional risk.
Heavier stomach sleepers also run the risk of “hammocking” on a mattress which can cause lower back issues. It is the riskiest sleping position and generally requires thinner and firmer comfort and support layers. Side sleeping on the other hand ia a sleeping position that has more pressure points and generally needs softer and thicker comfort layers to provide good pressure relief. In cases where needs “conflict” … either between a couple or between different sleeping positions … it’s generally best to choose on the firm side rather than the soft side. Firmer mattresses can be easily softened for better pressure relief but mattresses that are too soft for good support and alignment are difficult or impossible to correct.
In general … there are really two approaches to buying a mattress. The first involves learning enough about mattress materials and specs and construction along with analyzing the specs of every mattress as part of your research and decision. This takes a significant amount of knowledge time and effert (especially to find out the quality information that can be very difficult to get). The second is to find a better local factory direct manufacturer or sleep shop that carries alternative brands that is more open about their materials and already has this knowledge so all you have to do is know enough basic information to ask better questions. These are the types of outlets that can be your best friend and are more likely to provide the information about what is in their mattresses so you can make more meaningful comparisons and decisions. The more they know, the less you have to know.
Some of the better choices in the Louisville area are in post #3 here.
Hopefully this has given you a place to start but if you have more questions along the way feel free to post.
Phoenix