OK, I brewed an IPA on Sunday and all went very well thanks to all the help from you guys here. Fermentation started about 8 hours later and when I got home from work it was aggressive but the temp was around 73. I cooled it down to about 64 and it is holding steady there. I noticed that the bubbles slowed down greatly as the temp fell, is this normal. As always thanks for the info.
This is normal. A slow and steady fermentation will produce less CO2 compared to the same time period of an aggressive fermentation. The yeast are still happily doing what they are supposed to do. Fewer off flavors will be produced by cooler fermentation temperatures in the low to mid 60° range.