Shouldn't be a problem, cockatoos are more tolerant of higher pH than other apistogrammas. My Cockatoos have been doing just fine (even breeding) in a pH of 7.5. What was the pH before? How much has it moved? Try to determine what may have caused this and keep an eye on your pH. In the mean time, I wouldn't mess with it. If it continues to rise, partial water water changes will help.
Congrats on the new additions!