Diaper Rash

We've been having some major problems with diaper rash in the Ski household the last 2 weeks. Some of it stems from the horrible heat we've been having here and the fact that our baby is always hot and sweaty. Other reasons are because the diapers we are using are getting smaller but are still 'ok' according to the weight recommendations. This has never really been a problem for Libby so we weren't exactly sure what to do. We've tried everything under the sun to remove and prevent the diaper rash - Butt Paste, Desiten, wash with a wash cloth versus baby wipe, towel dry the area off after diapering, changing every hour or when we know a 'present' is in the diaper, etc. Everything we could think of and things we got as recommendation from family and friends (thanks!). The thing that seems to work best for us is to change every 1-2 hours, use cornstarch (there are mixed reviews on this), and use Balmex. So, when you are completely frustrated by the diaper rashes that appear - don't ever give up!