can I use a bul,b for an average of 15/9, for 2 years?

I just bought a new adjustable 600w hps setup to create a separate grow room from my bloom room. It happened to be at the same time I needed a new bulb for my bloom room. So, I took the new bulb that came with the package and used it in my bloom room. I took the old bulb t and put it in my new setup... in my grow room. Follow me?

Well, my new ballast, in my grow room, can run on 400w, 600w, and 600w turbo. What I would like to do is run a new bulb in my bloom room, @ 600 watts, for a year. Then, I would like to use that same bulb, in my grow room, to run @ 400w, for another year.

So... one 600w hps bulb run @ 12/12 for a year.... then run at 2/3 strength (400w) for another year @ 18/6. Is this too much usage for the bulb? Should I just bight the bullet and buy two new bulbs every year... perhaps the bloom room gets a new bulb every 6 months... the grow room gets a new used bulb every 6 months.

I am using a hortilux super hps btw

I must be too high. I'm not following at all.

Why would you want to do that. Hid bulbs start to degrade after 6 months. After a year your yield will suffer. Replace bulbs every 9 months.

If you want to veg with it later on that would be fine. Just dont flower with it after 9 months.