Sounds like you have some history with the PPCs you selected. However, I have a hard time believing that 2 second-tier PPCs have enough supply to be able to send your site over 1000 uniques per day. I’ve tried several PPCs and have found the one’s that deliver “real” traffic only provide a few clicks per day, while the one’s providing tons of traffic turn out to be scams. You should be checking your stats to see if the traffic is real or not. You can pretty much tell if no-one makes it past your home page. Beware of PPC in this industry.