said by swintec:
what is the mattress and box spring sitting on? a headboard and footboard with side rails or an actual frame? Is there an actual center support going across the middle WITH a foot on it?
Yes, it has a center support that touches the floor. I've even tried it with the box spring on the floor for ultimate support and it doesn't make a difference. I think it's just the material that is being used which is the issue, not the springs or the insides of the mattresses.
I remember a similar explanation when I would have them replaced under warranty. Even this latest one, I slept in different spots for the first few months, which seemed to help, but now it's back to being junk. Divide the mattress into 5 spots for example (cut into 1/5ths). If I sleep in spot 1, spot 1 becomes soft eventually and isn't as firm as the 4 other spots. Sleep in all evenly, and the whole mattress isn't as firm as it was. Only takes a few months to exhibit these issues in a "better" mattress.
I've seen a few places offer double sided mattresses, but with this mattress still under "warranty" (ie. they'll probably tell me to piss off this time), I don't want to spend $700 on something that shouldn't be having this issue.
I have a mattress from a different place in a different room that felt firmer when I bought it, but it has the same issue.