Hi Kiana Claire,
The better options I’m aware of in Hawaii are linked in post #2 here. I would call each of these to see what they currently have available because what they carry can change.
A mattress is only as good as the materials that are inside it. Unfortunately the attachment you posted to the Serta Marengo is mostly marketing information and has very little information about the layering or what is in the mattress. You can see a little more about what is in it here though.
A few comments …
Product Detail
Quilt
Fireblocker Fire Barrier System: Part of the fire barrier system
Serta Pillo-Fill: This is a polyester fiber fill. It is subject to packing down and compression over time
Soft Convoluted Foam: This would be low density/quality polyfoam. They don’t provide the thickness or the density information but it would be part of the layers that were subject to early softening.
1/2" Comfort Foam: Low density polyfoam that is subject to early softening.
Top Upholstery
Fireblocker Insulator: Part of the fire barrier system
1" Comfort Foam: Low density polyfoam that is subject to early softening.
1 3/8" Soft Zoned Convoluted Topper: More low density polyfoam.
Support System
532 Continuous Coils Innerspring System: this is the innerspring. Continuous coils are among the most inexpensive innersprings on the market.
Foam Encasement: This is polyfoam that surrounds the innerspring to provide a firmer edge. Also subject to softening if you sit on the mattress and possibly loosening from the edge of the springs
Overall these are lower quality materials but most importantly the comfort layers use the type of foam that is subject to softening much faster than higher quality materials. This loss of comfort and/or support isn’t covered by warranty unless the foam reaches its final stages of breakdown where it permanently loses its ability to rebound and any unweighted impressions are deeper than the warranty exclusion. The mattress will typically need to be replaced long before this happens.
Usually a topper is used to add to the softness and pressure relief of a mattress where the comfort layers are too thin or firm. It can also change the “feel” of a mattress depending on the material you use. It can also extend the life of the materials below it by taking up some of the mechanical compression forces when you are sleeping on the mattress.
The risk of a topper that is too thick and soft used on top of a mattress that already has fairly thick/soft comfort layers (such as the Marengo Eurotop) is that it can make the total comfort layers (topper and mattress) too thick and put you too far away from the support system of the mattress which could risk support/spinal alignment. It doesn’t say the thickness of the soft convoluted polyfoam in the quilting (hopefully it’s very thin) but there is almost 3" of polyfoam (plus the thickness of the convoluted polyfoam in the quilting) so the addition of a topper could be quite risky when it is added to comfort layers that are already that thick and soft.
Since unfortunately you are “locked in” to a Serta (which like most major brands are generally poor value), you may be better off choosing the firmest version of the Marengo (see here) which has thinner and firmer layers of polyfoam and would be a better candidate for a topper. In this case the topper could add to the pressure relief of the mattress with much less risk to alignment, perhaps improve the feel (depending on the type of topper you choose and your preferences), and would also extend the life of the cheap polyfoams that are used in the upper layers. If you do go in this direction … the key would be to add the topper as early as possible because if the cheap foams soften under the heavier parts of your body (hips/pelvis) … then the topper will only “follow” the soft spots.
The “weak link” of a mattress is generally soft and low quality materials in the comfort layers which will soften and/or degrade much too quickly. If you are considering an exchange to another Serta (the firm marengo or any other one they carry) … then knowing what is in it so you can identify the weak link of the mattress is very important.
Hope this helps.
Phoenix