After just six minutes, Stuart Fleetwood conjured up the first chance as his 20-yard lob hit the crossbar.
Nine minutes later, Silkmen goalkeeper Jose Veiga dropped a Joe Colbeck cross at the feet of Ryan Green who smashed a close-range drive against the bar.
Green did not have long to wait and was first to react when Veiga dropped a Waide Fairhurst free-kick to fire home from close range in the 21st minute.
The game changed on 54 minutes when Hereford skipper Michael Townsend clipped the heels of Matty Hamshaw in the box to earn a red card, allowing Chalmers scored from the spot.
Macclesfield then took the game by the scruff of the neck with Hereford keeper Adam Bartlett brilliantly tipping wide a Hamshaw drive before blocking a 15-yard bullet from Tyrone Barnett.