Hi selder.
Sorry to hear you’re sleeping hot and uncomfortably!
I took a look at your Prana mattress and while the specifications are reasonable, I think you’re being overheated by the quilted layers (the cover) as there is quite a lot of synthetic material there:
Quilt: 100% Polyester cover
1" Soft HD foam 1.5LB
1" Firm HD foam 1.5LB
Comfort Layers: 1" Medium Talalay Latex
1" Everlast foam 4LB
The latex, which would sleep cooler, is sandwiched between heat insulating foam layers trapped in a polyester cover. There is more about the many variables that can affect the sleeping temperature of a mattress or sleeping system in post #2 here that can help you choose the types of materials and components that are most likely to keep you in a comfortable temperature range.
I think looking into something like the Natural Escape or Pure Echo is well worth your time. Organic doesn’t necessarily mean “better” and often boils down to who has the adequate space and money to offer that sort of certification. That said, if chemicals are something you’re worried about in the slightest, organic and GOLS and OEKO=TEX certifications are things to look out for.
I would agree that you may get your most comfortable nights sleep on a mattress that does not include poly or memory (or gel) foam.
The difference between Dunlop and Talalay is often described as the difference between pound cake (dunlop) and angel food cake (talalay). 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 however is also used in the comfort layers because of its firmer and less “lively” nature which is attractive to some who prefer its feel. Latex is also the most breathable of all foams and this can be an important part of temperature regulation for those who tend to sleep hot. There are also versions of Talalay latex available that are specially formulated to help regulate temperature (Celsion latex is one of them) for those who need it however even the regular forms of latex perform very well here.
A number of our Trusted Members offer latex hybrids with cotton and/or wool covers as opposed to polyester! I’d suggest looking through our directory, keeping in mind that no matter who you buy from, it is important to have a detailed conversation with whomever you choose to purchase from 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 so they can help you choose which may be your best fit from their inventory.
NikkiTMU