metal halides

ok so i am in the process of setting up a 150 gallon tank and i am going to put 2x250 watt mh and was going to get the 20000k buld my question is what kinda bulbs should i get? hqi, sodium,?????? whats the diffrence? what is the best kind of bulb??

 

i prefer HQI. I have a 2x250 14000k HQI bulbs on my 70 gallon and it works like a charm!!! The corals thrive under it. I actually have never heard of a sodium bulb but i am sure that just about and MH bulb works great! Good choice on the MH. You are in the right direction.

 

Is that 150 a 4' or 6'?
There is no best kind of bulb. It's all preference. I personally like HQI bulbs. Some say they are more maintence because it takes more work to change the bulb. But you have to have a glass shield to filter out the UV.
With SE, you don't need a shield, but you have to worry about splashing. If you want the 20k Radium, you have to go Single End.

Do you want a yellow look? Blue look? White? White-ish blue?
Do you want more growth, color, or a good mix?

 

I realy like the blue look but i also want alot of growth looks like i cant have both

 

Actually, you can live with both. Growth may be slightly faster with an iwasaki 6500k just because it has such high spectral outputs of every wavelength. Overall, the "10k for growth and 20k for looks" is not true. Go with either a Phoenix 14k or a radium 20k for both looks and growth. These two bulbs have a high peak around 450nm, which is great for looks. They also have higher UV values which helps in growth. If you have a choice get an electronic ballast and a nice reflector like a lumenmax or lumenbrite with SE bulbs. Other great bulbs are the ushio 14k (more of a crisp white look) and the SPS 20k (blue)