PAR and PUR
- Thread starter chs724
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PAR is photosynthetic active radiation and PUR is photosynthetic usable radiation.
Basically, PAR is what your lights are outputting and PUR is what your corals can actually absorb and use out of that energy. Because of this, PUR is probably more important but also much harder to measure and quantify as it varies across coral types.
PAR is much more readily measured in our hobby and combined with the right spectrum balance, will create a healthy PUR value. BRS did a good video on this which is worth checking out. PAR and spectrum are both readily measured and when balanced create the right environments for the corals of your choosing.
Basically, PAR is what your lights are outputting and PUR is what your corals can actually absorb and use out of that energy. Because of this, PUR is probably more important but also much harder to measure and quantify as it varies across coral types.
PAR is much more readily measured in our hobby and combined with the right spectrum balance, will create a healthy PUR value. BRS did a good video on this which is worth checking out. PAR and spectrum are both readily measured and when balanced create the right environments for the corals of your choosing.
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chs724
Community Member
Thx for your response. I have seen the Video before. The reason i am asking is that the seneye shows higher PUR when i tune down whites but lowers PAR at the same time. so i was asking myself what would be better. I know most people say set PAR and you will have good PUR as well but what if i could neglect some whites and get better results.
Thx
Homebrewer
Active Member
You likely could do exactly that. BRS has also put out videos about best wavelength, and there is ongoing debate regarding blues vs. whites vs. full spectrum (and everything in between). From the research I’ve read, and in my opinion, both the energy level (PAR/PUR) and wavelength are both important, with the blue spectrum in the 420-460nm range affecting growth the most.
You could blast corals with tons of energy, but if they are unable to use it, I don’t see the benefit. Likewise, you could dial in the perfect wavelength, but without enough “power” behind that, there isn’t enough energy for growth.
Right wavelengths at right levels is the key, and moreover, it just makes logical sense.
