Clone pools, not seeing any traffic to the pool

I'm working with a customer with a similar issue. I think we were able to get the Clone Pool feature to support them but they're saying they're not seeing cloned traffic on their test clone servers. We're seeing connections and data increasing on their cloned servers so I know that we're forwarding data onto the clone pool members. Is there a way to actually tell if the clone pool is receiving cloned traffic from it's primary pool? Is there a tcpdump syntax that I can use?