not good, that's an arching sound of electricity. Check the bulb's tightness in the socket. When you replace that bulb move up to a hortilux blue.
Had exactly the same problem today and thought it was the ballast or needed a new bulb, just took it back out and screwed it back in firmly, worked straight awaynot good, that's an arching sound of electricity. Check the bulb's tightness in the socket. When you replace that bulb move up to a hortilux blue.