My seedlings are dropping like flies, please help!

The strain is blubonic and the growth medium is coco. This is my first grow as well. I germed the seeds in a wet paper towel and they all worked fine. I thought I'd skip the rockwool cubes and go directly into the small 500ml coco crouton pots, so that's what I did (this was probably a mistake). I also used a low dilution of nutes from the beginning, which I now know was also a mistake. Anyways I stopped the nutes a week ago (these are now two weeks old) and have been feeding with plain water for a week, flushing once daily. THe stems have all been shriveling up and dying and I don't know why. I tested the PH yesterday it was around 7, so I flushed them all with ph5 water to get the crotuons down to ph 6 but no improvement yet. The other day the leaves all strted to point upwards (see pics).

I'm thinking this may be a calcium, deficiency, as I inspected the roots from some other seedlings that had died earlier, and the roots were brown in places and not very developed overall.

Light started out as a single CFL overhead about 15" away from the plants for the first week, and they also recieved some indirect daylight. At the end of this week a few of the stems were beginning to shrivel, so a built a much brighter light box for them with three 54W T5 bulbs (15K lumens) about 4 inches away. SInce going in the box though there has been no new grwoth and things ahve only gotten worse!

I'm pretty sure this first batch of ten is a loss, but I don't want to repeat it again so I'd really like to figure out what the problem is.

Here's the stem issue:


And here you can see the leaves pointing upwards:

damping-off (plant disease) -- Britannica Online Encyclopedia i haven't opened this but it should explain everything,more than likely over watering

Flushing once daily... Aka drowning the plants. You shouldn't even be watering daily.

Well it's coco so the water runs off almost immediately, I thought it was nearly impossible to overwater with coco because of this, but thanks you guys know a lot more than me, i'll hold of watering for a bit hopefully there will be some improvement.

I have never used coco so maybe it is different. Need a second opinion...

yeah your first main problem was skipping the rockwool and going straight to coco.

rockwool is good in that it retains some moisture, while still offering healthy root penetration. in this way, by starting with rockwool, you can just water once, let it chill, then visibly be able to tell when it needed watering, rather than guessing with coco.

cannabis likes dryspells.

your second major mistake was starting off with a nute feed; what nutes were used and how much per gallon of water? this probably caused PH problems early on, as your PH is super high for that type of medium. your PH needs to be more around 5-6.

overall, your plant looks like it can't develop roots. next time go with the rockwool starter, mist a few times a day rather than watering so much. start with just water, 100ml or untill the soil is reasonably moist, then let the soil get dry before another healthy watering.

don't start nutes until the plant is at least 10-12 inches high, depending on what type of soil youre using.