What is the correct send and receive strings syntax for health monitoring of multiple servers in a pool ?

There is a string, Maximo in the response from the server but the F5 seems to still mark the servers down. If I replace the receive string with OK or Maximo|OK it works. Using 200 OK does not work.

The most important question that I need answer to is what is the most efficient way to monitor all the servers in the same pool considering that they all listening on different ports ? Do I need multiple monitors ? Can I use the dns name of the the VIP instead of real servers' dns names in the monitor ?

Thanks