How can I prevent these light burn issues?

My mistake I added the wrong light I actually have the ts600 it’s a 100w led. I just updated my diary. I’ll try moving the light way up. I only watered once when I put the seeds in soil and it has been moist since so have been holdi off on the water. I will also turn my exhaust fan up a bit to help draw out more moisture. Thanks

I run HLG lights and I get the red stems too. I think it’s an LED thing. I would say like some others have said you just need to learn how to play with the light you have to fin that sweet spot. And yes getting a PAR meter really takes a lot of the guess work out.

The problem is coming from the light being too intense for the size tent your using, this light is recommended for a 3x3 grow space, it's also recommended to have it around 60% at a height of 16-20 inches above the canopy.

I have multiple Mars lights and they work fine, I literally have a plant 1inch away from my light and no burning or bleaching is happening, seedlings always seem leggy(to stretch) when they get bigger they grow out of that little red stem. I suggest you do some more research on this or your gonna have a hard time growing but I wish you the best of luck.

So I don't have any Mars hydro lights but I hear good things about them. You can get a par meter app on your phone to help dial in light intensity. As for the issues you're having I think it's more likely to be an overwatering issue more than the light. Try to decrease the watering so you're only adding an ounce or two a day for the first few. Then the goal is to water every second to 3rd day in soil. Coco can be daily but I still tend to aim for every second day to be safe. There may be other issues aswell but just from what I saw in your journals photos. You want/they need the soil to dry out a bit to breathe

When my plants are in seedling stage I'm at 30 inches with light and it dimmed to 40%. If you have a dimmer I would turn it down. If not raise your light.

I had my lights 40 inches over my seedling at 100% its not a mars but running same samsung diodes. I think you just need to find that sweet spot. Mars hydro is a good brand.