According to a foam expert, the foam Hunter uses is not for everyday use, but for a weekend once in a while, so if anybody has slept in it for an extended period, it is worthless. Go to a local foam store or order some from online. Most good quality foam is treated against mold and I haven't had any problem...even in winter time when the bottom of it is soaked.
The other problem is that Hunter only puts 3.5" of foam back there and it needs to be at least 7" (also from foam expert). I replaced mine with 4"of second hardest grade A foam because I didn't want to loose the headspace. That worked well for about a couple of months so then I went to walmart and got a memory foam. It was 2.5" of medium foam and 1/5" of memory foam. I put that on top of the existing foam to equal 8" total. It is now the most comfortable bed I've ever had.
Also from the expert is that don't expect even the best quality foam to last more then 4 years. Latex is supposed to last a lot longer but also costs a lot more too. Personally, I like the idea of replacing the bed every now and then; it gets rid of the bed bugs.