Par reading for T5

jda · Feb 19, 2018

I SOOOOO wanted to test some T5 bulbs, but the sphere that I got to use was only 24". I hope that you get a 50 or 72 inch sphere.

The full-spectrum sensor still neglects spectrum above 400 and a most below it... although it is better that the old ones.

madweazl · Feb 19, 2018

This is from Apogee's website so I'm not sure how accurate it is but the specs show it reads down to 389nm relatively well. I'm not sure if this is the same one Dana Riddle compared with the Li-Cor or not (may have been the previous model as he mentions a newer model coming out in the article). If it was the older sensor, it was within 10% of the Li-Cor's measurements at the bluer end of his tests (though I don't know the exact range tested).

jda · Feb 19, 2018

It captures about half the output of an Actinic Bulb and misses about 30% of a good MH bulb. It also oversamples 450 to 600nm. It captures nothing past about 675 and I think that waves from 350 to 850 are very important. It captures nearly all of most LEDs, which is helpful.

It is a very good hobby-grade tool, but not a good industrial/science tool. I am happy with mine... it gives a rough reading that when you use some brains to apply the type of bulb can be a good guide. I am happy for what I paid for it... I do not want to spend $20k for a more accurate reading.

My only small complaint would be if they named it visible-spectrum instead of full-spectrum.

madweazl · Feb 19, 2018

Do you know if the portion that is over-sampled is mitigated in software? And perhaps there is something happening in software in regard to that which is under-sampled as well?

jda · Feb 19, 2018

I do not know for sure, but most of these sensors just "count" what they can sense... they do not differentiate between which wave is which wave. You would have to incorporate a spectrometer with it to get that. That would be totally cool, though, if somebody made a $400-500 spectrometer and output meter.

jimmyzhou · Feb 19, 2018

My tank 48x24x24 120 gallon I have par meter Soo. When I test my par. For the t5. About 12 inch above water input the part meter right under water Read about 160. Under 8inch water read 110-120 sandbed can read as 50-80. Was the new aquatic life t5 hybrid. Add 2 radion xr15 turn too ab+ run 100% of them. Par read right under water around 300-340. 8inch read 200-240 sand bed read 160-200 The t5 lightbulb I’m use 3x blue plus 1 coral plus.