Do i need a new bulb?

[Flow863]

I bought my coralife hqi 150 watt metal halide light off craigslist about 2 months ago and my corals have not been doing so well. I cant figure out why. My zoas have lost almost all of their color and barely open up. My water parameters are
calcium 480
Dkh 11
Ph 7.8
Nitrite 0
Nitrate <20
Could it be that i need a new bulb and they arent getting enough light?
How will i know if i need a new bulb?

 

[bavass]

what are the phosphate levels?

 

[jose7878]

Could be they got light shock with the new bulb.

 

[uh.oh...]

yes, too much too soon could have been the cause. Try putting some screen or egg crate on top of the tank, above where the corals sit. Or just raise your MH a few inches more above the tank

 

[Flow863]

I havent tested for phosphates but i use rodi water so they should be low.
The guy i bought the light from told me that the bulb may need replacing in a month or two so i assume its a pretty old bulb.
I just ordered a new bulb so hopefully that solves the problem
=/

 

[jose7878]

When you said you bought your corallife hqi

 

[jose7878]

You didnt mention that they were used. Then yes your probably due for new bulbs.

 

[Flow863]

Oh crap i didnt even notice
sorry
So do you think this will solve my problem with my zoas?
I hope so
=/

 

[jose7878]

Try putting some screen or egg crate on top of the tank, above where the corals sit. Or just raise your MH a few inches more above the tank

Remember to do this when you get your new bulb.

 

[jose7878]

Oh crap i didnt even notice
sorry
So do you think this will solve my problem with my zoas?
I hope so
=/

Could possibly.
You mentioned that you use ro/ di water check your phosphate cause once my ro water reaches 1 TDS I start getting phosphate in my ro water. So that could also be something to check.
I