Hi zkimmer,
A 70 - 100 kg/m3 density range is a fairly wide range of firmness levels from the high teens or lower 20’s (soft) to over 50 (ultra firm) in terms of an ILD equivalent (see post #2 here).
[quote]I can do one of two,things:
- Purchase a topper
- Replace one layer with the topper. For example, topper-70-75-80.
There is a nominal cost for option #2. Option #1 is more expensive, but I do not want price to be the defining factor. The mattress is lovely, and will give us many years of comfort. What would you do? [/quote]
What would work best for me and what I would do could be very different from what would work best for you because only you can feel what you feel on a mattress and there are too many unknowns and variables involved for anyone to really know which one would work best for you with any certainty. There are a lot of “it depends” in which one would have the highest odds of success.
There are some suggestions in post #2 here that may be helpful but the first thing I would suggest (outside of some of the “non mattress” suggestions that are mentioned) would be to “do nothing” for now until you have slept on your new mattress for a few weeks (preferably 30 days or so) so that it has a chance to break in and your body has a chance to adjust to the feel of a new sleeping surface. It can be surprising how much your experience changes over the course of the first few weeks of owning a mattress.
If after a few weeks you are still finding the mattress too firm then it would be the best time to consider your options.
The most reliable way to choose between them once you are more “familiar” with the feel of your new mattress would be to test both options in the store to see which of them was the best match for you in terms of PPP (Posture and alignment, Pressure relief, and Personal preferences).
Having said all that … If it was me and the only issue was that the mattress was just a a little or a fair bit bit too firm but not “a lot” too firm and you just need some additional pressure relief then I would probably be leaning towards option #2 which would result in a mattress where both of the top two layers were softer than your current configuration so it would be noticeably softer and more pressure relieving for most people and would have a reasonable chance of being “enough” but your own personal testing and experience will always be a more reliable source of guidance than any speculation based on “theory at a distance”.
Phoenix