Share 'Tempering help'

I was wondering if you need to use seed chocolate to acutally temper? Could you temper the whole batch? like say i bring the whole 5lbs of chocolate down to 80 F and then heat back up to 90 - 92 F?  I'm about to buy an ACMC machine and im in the tropics where the ambient temperature is 33 C. So I will have to temper in an airconditioned room where i bring the ambient temp down to 24C. I use a S…