Rob,
JMO, but if this was my 60g, I'd be doing weekly water changes of about 8g. I'm a real stickler for weekly maintenance
, including cleaning glass, filter media and pumps. Pumps can easily get gummed up with crud, which is yet another source of nitrate and phosphate. Clean pumps also function optimally.
I do this exact weekly maintenance on my 72g, 42g and 28g, as well as turkey basting each tank the day before the water changes to export even more nitrate and phosphate producing crud.