i am a newbee help please!!!

hi folk this is my first post in this forum forgive me if im posting in a wrong please here is my question
my light goes on and off every 5 minutes ballast making sound when the light goes off kind of tikking noise, i have been using the light over 1 years its 400 hps light .
1.why the light goes off like that?
2.how to know if the bulb is over?

i have 1 m2 grow room 6 plants with my homemade ebb & flood system(hydroponic) i use advance nutrients, i have been growing indoor last 2 years thanks in advance

Please replace that HPS bulb. A year is a long time for a HID bulb, and your yield will be low from loss of brightness from a lamp that old.

MOST IMPORTANTLY, there is a fire danger, a lamp on it's last legs will shut on and off like that, and in that stage there is an explosion risk. You could be seriously injured from molten glass, and also a fire could start.

Stop using the lamp and replace it as soon as you can.

Oh yeah, this is the wrong forum, next time try Basic Growing or something like that.