That sounds pretty similar- I like to use what I call the "bobbing bucket" method of temperature control. I use an aquarium heater to heat a large bucket of water and float the fermentation chamber (sealed bucket with an airlock) in it.You do exactly what I do I pitch high and wrap it up to hold the temp for a few days then let it slowly go down to room temp. I then keg after 10 days.
it must have been releasing some CO2 which was making the airlock bubble but since that my next batch went to plan