I’m just trying to save you a bit of hassle bro.
I've been thinking about why I wasn't using the T5 and am using the Mars and, rather than using just the Mars, there's a lot of benefit to using
both and I appreciate you pushing me in that direction.
The good thing about a T5 is the amount of blue light but the 18 watt bulb only generates a PPFD level of 50. On the other hand, the Mars can generate a very low amount of light but its spectrum is balanced so there's nowhere near the percentage of blue in its payload. Put another way, the 50 µm/second of light from the T5 has a pant load more blue than 50 from the Mars. So, the best of both worlds is…
I can hang the T5 in the tent and use that to supply a blue-heavy "baseload" of 50µm/second and use the dimming feature of the Mars to add in the rest of the light that's needed.
The reason why this has been buzzing around in my head is that the tallest seedling started leaning really badly so I used a toothpick and a twist'em to hold it up and then bumped the light level up. Leggy, weak stems can be caused by too little light so I added 20µm/s. The plant straightened up within a few hours.
Blue light can be used to keep plants compact. Turn that around and lack of blue light will tend to allow plants to get tall and I think that's what happened. When the seedlings were really young, they were under the T5 and I noticed that the seedlings were short with thick stems. After lighting up the Mars, they grew tall but thinned out. I didn't connect those dots till tonight.
I'm hoping that by adding in the T5, the blue light will help the seedlings grow compact and strong rather than tall and skinny. That's just a theory and, you're right, something documented in a grow journal.