Stacey, there is no point to doing a temperature match on new water for a fishless cycle. Do nothing to your water pH unless you are keeping fish that actually requires it or you have a pH below 6.4 during a cycle. Some people among us overreact a bit to changes in water. Once you are ready to place fish in your tank, as it seems you are, it is best to allow the tank to reach tap water values if they are even close to what your fish "need". In my own experience, fish are quite adaptable to any steady value but they are not able to respond easily to chemical changes caused by additives. Leave those darned things at the LFS. The 83F temperature is far too warm for almost any fish so find out what your stocking might need and adjust the heater accordingly. My bet is you will find a value somewhere between 72F and 80F as a best compromise for a wide variety of fish that you might choose to add. Since I have mostly rarer livebearers like goodeids, many of my own tanks run in the low 70s.