Par

[kinerson]

Could someone please explain to me some details as to how important PAR is to a reef tank? I understand that it is the "photosynthetic available radiation" but...

Is it more important with sps an less important with softies? Does deeper water species benefit much from a bulb with a high PAR value verses one with a lower value.

I've been doing some research on lamps as I am preparing to replace my old 175w halides and have found bulbs that range greatly in PAR value with minor price differences. Any reason not to go with the highest PAR value you can get?

Thanks,
Greg

 

[BeanAnimal]

PAR is just referring to the amount of light available that the corals can use. The higher the PAR, the better. You will however find that the more yellow a bulb is, the more PAR it puts out. At some point you need to trade PAR for aesthetics... or add actinic supplementation to get the desired look you want.

 

[Henry Bowman]

Bean's got it right !

My 2 cents.... Think of par as the amount of energy at a given color range that is available for your corals. SPS require more PAR than do LPS corals (in general, there are exceptions). The reason not to go with the 'highest" par would be as Bean stated astethics. I'd tend to head toward the 14K range if you dont have actinics or supplemental lighting to deepen the blues in your tank. Again as Bean said, the higher par lights are the 6500 - 10K bulbs. You have probably noticed as you get toward the 20K bulbs, par drops off significantly. Not at all to say 20K's are bad bulbs ! You'd have to chose a bulb with the coral's light requirements in mind then the overall look you like.

 

[BeanAnimal]

hehe I never did mention 6500 as they are soooo yellow that i foget they even exist