Hi Axiom81.
Welcome back to our Mattress Forum. 
I’ve started having lower back pain when I wake up in the morning.
I’ve tried a topper from Nest Bedding (thinking maybe it was a bit firm)…but that didnt help. I then ordered a Latex Topper (2") from SleeponLatex. I will say I love the feeling of Latex and the topper…but I’m still having lower back pain.
The Nest Bedding Alexander Hybrid has 3" of Titan Chill foam comfort layer. As a 100% back sleeper, the “gaps” in your profile are not quite as deep as for side sleepers, a slightly thinner top layer will generally work a little better. I am not sure which comfort choice you had but it may be that for back sleeping, a slightly shallower cradle was needed. The lower back pain in the morning leads me to believe that your spinal alignment might be compromised. It is important that you determine the cause of the issue you are having before attempting to find a solution.
I always suggest a “ground up” assessment to make sure that there is nothing under the mattress that may be contributing to the issue. Bed sizes above a twin should have good center support to the floor to prevent any flexing under the mattress and the people sleeping on it. In all cases … the mattress needs to rest on an evenly supportive base that will not sag or weaken over time under the weight of the mattress and the people on it. You can verify if the support system you are using is appropriate if you place your mattress/spring unit directly upon the floor to see if that makes any difference for you. if you feel any improvement then it is possible that the support system is the cause of your discomfort. Also, because your mattress encasement is zippered it would be easy enough to check if either the top comfort layer or the springs unit are sagging or defective. If you find any reasons for concern then you can contact Nest Bedding directly as the mattress is still in the warranty period.
The good news that you have determined that you like latex which is mostly preferred for Its liveliness, resilience, support, and being temperature neutral qualities. If you did not do so I would recommend that you replace the 3" Titan Chill foam with the 2" latex topper and sleep on this configuration for a few days to give time to your body to unwind and readjust. I’d keep some notes with your findings to collect a few more data points. In terms of comfort, a good starting point for a 100% back sleeper is 2" of softer material on top of any core layer you might have and then increasing or decreasing from there depending on other factors like weight, preferences, or other sleeping positions. You can also replace the Tian Chill with the 3" with the Sleep on Latex layer if you still have it and collect additional data points.
Dunlop has a different “feel” and performance than Talalay and is less lively or springy. You can see a comparison between them in post #7 here but your own experience is really the only way to know which one you prefer with any certainty. Some people would notice more of a difference than others with transition or support layers that used each material if the top layers were the same type of latex because you will “feel” more of the upper layers than the deeper layers … at least when you first lie on a mattress. Talalay latex is the most popular as a comfort layer because it can be made softer than Dunlop and is more consistent in its softness across the entire surface of the mattress. Dunlop is also used in the comfort layers because of its firmer and less “lively” nature which is attractive to some who prefer its feel. As you’ve expressed a preference for something softer, Talalay would be a good direction to go.
In general, both all latex and hybrid latex mattresses can be more than adequate in terms of quality and durability. I am guessing that you are looking to find if the all latex mattress specific qualities would be a good match for you. The answer to this question is fairly complex and it is better explained in technical terms but it really boils down to personal preferences and feel.
Latex and all foams have a quality called “hysteresis” which is the ability to absorb energy. Latex has a hysteresis of around 20% to 30% which is the amount of energy absorbed. Innersprings retain almost all their energy and so will “bounce back” or “push back” much more strongly but this is also affected by the type of materials that are used over the innerspring. The “opposite” of hysteresis is resilience which is the height of the rebound a material gives when a ball is dropped on it expressed as a percentage. Innersprings have a higher resilience than latex. This means that an innerspring mattress will be more “springy” than latex or other foams and those who have tried both will validate that the feel between them and how they each react to motion is very different. Some prefer one while other prefer the other. Both can make high-quality support layers.
and more detailed information about innersprings vs latex support cores in [url=https://forum.mattressunderground.com/t/all-latex-versus-latex-top-on-inner-spring-mattress]post #2 hereBoth innersprings and a firmer latex core can be used as a support layer and each has very “different” characteristics but the most important differences are the ones you can feel and that you personally prefer. Both can be softer or firmer depending on design so a pocket coil could be firmer than a latex core or the other way around they could be zoned or not all depending on the specifics of the components you are comparing. There is more about this in and more about the different types and blends of latex in this article and in post #6 here or post #29 here
You already determined that you like latex feel. The next step is to experiment with different configurations as suggested above to determine the possible cause of the back pain and have some insights about the level of comfort support you need. for your average BMI and sleeping position (see this article about sleeping positions ) This approach is less “overwhelming” as when the focus is on your needs and preferences then you establish a set of criteria which helps eliminate any options that do not meet it.
If you are strictly thinking of replacing your current mattress then of the companies you mentioned, Sleep On Latex and Sleep EZ are Trusted Members on our site. All of our Trusted Members are extremely knowledgeable and compete with the best in the industry. If you present them with your sleeping specs, comfort/support needs, preference, etc. they will be able to help you choose a configuration that is can best match your needs and preferences.
I would also suggest checking out the following:
Arizona Premium
FloBeds
Latex Mattress Factory
Nest Bedding
Foam Sweet Foam
My Green Mattress
Luma Sleep
These are just a few so I’d definitely have a closer look through our directory for additional latex mattress options (both all-latex and hybrid).
Regardless of which mattress you ultimately select, I’d make sure to have a detailed conversation with your finalist retailer/manufacturer and provide them with your stats, body type, sleeping styles, general preferences and history, some general information about your current mattress, or what you have tested, and any other specific information or circumstances that could affect your choice of a mattress.
Looking forward to any future questions or progress reports you may have for us.
Phoenix