Domain Controller Synchs DHCP improperly

We have a primary domain controller with DHCP on it and a secondary domain controller with DHCP located on it. Our primary domain controller went down, thus passing on responsibility to the secondary domain controller. The secondary domain controller’s DHCP server is not properly dishing out ip addresses. We have conflicts. When the primary domain controller dished out the ip addresses, then the secondary domain controller kicked in, the secondary DHCP server got confused and we had lots ofip conflicts. We realized that it never was working properly. Any suggestions would be much appreciated. Thank you.