Hi blewis341,
The specs you listed don’t include the most important information which is the foam density of the memory foam and the polyfoam. Without this … there is no way to know the quality of the mattress, any potential weak links in terms of durability, or make meaningful comparisons with other mattresses.
3" Advanced Visco Technology Memory Foam: You need the density of this layer in lbs/sq ft. This is a potential weak link
2" layer of pressure relieving foam: This is polyfoam and you would also need the density. This is also a potential weak link.
7" high density support core: This is also polyfoam but is probably 2.2 lbs (although I would want to know this for sure as well).
CertiPUR-US® approved: Without this … I wouldn’t consider a mattress that used Chinese foams as this one does. With it I’m OK
Embossed 80/20 cotton blend velour cover: Probably fine although it doesn’t say which number is the cotton or what the rest is (likely polyester).
Once you have this information along with the price you will pay … you can at least tell the quality and make meaningful value comparisons to other choices you have.
It would also be important to me to make sure you were dealing with someone who had the knowledge to help fit you to a mattress based on your weight, body type, sleeping positions, and preferences. The alternative to this for me would be a refund or exchange policy that costs little to nothing (including return shipping costs and any other fees) if you need to return the mattress because it isn’t suitable for your specific needs and preferences. If you aren’t dealing with someone who is knowledgeable about mattresses or haven’t done some local testing on mattresses that are very similar (and you can only know this if you find out the specifics of the layers) … you are really rolling the dice in terms of the quality of sleep you will have on the mattress.
No matter how cheap the price of a mattress … it’s wasted money if it isn’t what you need and prefer or if it turns out to use lower quality materials that won’t last.
I would tend to start over if your box spring is old and I’m also not a fan of using a solid surface as a mattress foundation unless there’s no alternative because it doesn’t ventilate as well and it can increase the risk of mold, mildew, and dust mites in the mattress. There are some good quality/value foundations in the foundation thread here and because you are looking at a memory foam mattress with a firmer polyurethane foam base, any of the choices there including some of the lower cost wire grid foundations would be fine.
Phoenix