Did some more digging on T5HO vs. LED. Unless you have a huge LED rig the T5HO still seem to stay ahead.
Here's a video. Don't know how deep the tank is. But if the light fixture is 25 inches long (bulb length 24" + say 1" for end caps) you can judge the depth. I estimate that the water is about 15" deep. Note the PAR at the bottom. At 1:07-1:10 it's about 90. That's with 2x24W bulbs AND not right under the bulbs.
Note that getting close to the front glass actually increased the PAR a little. Also note how fast the PAR on the bottom decreases when he moves the sensor somewhat close to tall stem plants (not even right under them).
So how come carpet plants that grow well in a tank and receive vastly different PAR do grow like an even carpet? How come you don't see areas that look great and areas that look just ok? I have seen an extreme example of that - a tank which had fresh green leaves growing in complete darknes (Java Fern, the back bottom side of the tank was in complete darkness because the thickly growing plant blocked all the light). To this day I cannot really buy the explanation that plants transport and shuffle nutrients and adjust the metabolism so the entire plant gets to live a life full of beauty and joy. Why on Earth leaves growing in complete darkness will be as green as the ones reaching the surface 3" below the light? Bottom line generalization is that when plants grow well they indeed do things that make no sense IF we just look at numbers and look at things from our limited perspective.
Here's a video. Don't know how deep the tank is. But if the light fixture is 25 inches long (bulb length 24" + say 1" for end caps) you can judge the depth. I estimate that the water is about 15" deep. Note the PAR at the bottom. At 1:07-1:10 it's about 90. That's with 2x24W bulbs AND not right under the bulbs.
Note that getting close to the front glass actually increased the PAR a little. Also note how fast the PAR on the bottom decreases when he moves the sensor somewhat close to tall stem plants (not even right under them).
So how come carpet plants that grow well in a tank and receive vastly different PAR do grow like an even carpet? How come you don't see areas that look great and areas that look just ok? I have seen an extreme example of that - a tank which had fresh green leaves growing in complete darknes (Java Fern, the back bottom side of the tank was in complete darkness because the thickly growing plant blocked all the light). To this day I cannot really buy the explanation that plants transport and shuffle nutrients and adjust the metabolism so the entire plant gets to live a life full of beauty and joy. Why on Earth leaves growing in complete darkness will be as green as the ones reaching the surface 3" below the light? Bottom line generalization is that when plants grow well they indeed do things that make no sense IF we just look at numbers and look at things from our limited perspective.