PAR Value?

[jzuse]

What is PAR value in regards to MH, I have found that
150W MH 10000K 90CRI 35PAR
150W MH 14000K 70CRI 35PAR
150W MH 20000K n/a 16PAR
250W MH 10000K 90CRI 56PAR
250W MH 14000K 70CRI 56PAR
250W MH 20000K n/a 26PAR
My tank is 24" deep so I have been told that that a 150W MH would be good but a 250W MH would be the best, now what would be the best all around K raiting? Please any advice would help? I am looking to upgrade before christmas.
Thanks

 

[acrylic51]

Your ballast your using factors into the exact PAR you'll get from different bulbs.....You could run the same bulbs on 2 different ballasts (magnetic or electronic) and have different PAR readings for same brand bulbs.....There was an interesting thread on another site regarding just this topic.....

 

[thomas712]

Those PAR ratings sound puny, I'm not sure I understand them. However if you would like to see some par ratings of 250 watt MH bulbs and ballasts follow this thread.
https://forums.saltwaterfish.com/t/144099/saltwater-aquariums-101-lighting
I get about a 835 Par rating out of my bulbs and ballast.

 

[kdfrosty]

Your PAR ratings don't look correct to me either. I have PAR of 795 with my current setup.

 

[reefnut]

Looks like those ratings are Photosynthetic Photon Flux Density (PPFD).

 

[sleeper]

But what *IS* PAR?
And how does it effect your livestock?

 

[kdfrosty]

copied from some "plant" growing site:
For growers PAR is all-important ~ and as important as lumens! PAR stands for > Photosynthetic Active Radiation.
Photosynthetic, the light sensed by a leaf pigment.
Active, the light that causes the leaf pigment to become active for making energy
Radiation, another word for light & photon energy
PAR is a measurement scale used internationally as a metric light measurement and is becoming more and more relevant to growing and greenhouse light measurement. Why is it important to you?
PAR is the measure of light that a plant actually senses and uses, and it is the light the plant sees and can use that is more important then the actual output lumen of the grow lamp!
* A large HID lamp may give out loads of lumens, but if it's too far away from your plant most are wasted (remember light intensity diminishes with distance) In addition the light a plant can use from these lamps is limited because the plant cannot see or use it because it is in the wrong spectrum.
So the main value of the PAR measurement is that it is the only measure that takes into account the actual light and light colours that the plant uses to energise its pigments and generate sugar energy, and it’s the sugar that makes your plants grow and produce such sweet fruits!