help with seedlings! distilled water, pH5.8, 80F burnt leaf tips, WTF

hey everyone, i need some help early in the game-
popped 18 critical mass seeds 10 days ago and all 18 germed. i have one big problem though, they havent grown at all in seven days...and are looking worse by the day

im running an 8 bulb T5 445W a few inches above the seedlings in canna coco, pH 5.8 and flushed coco before use. I water once a day and am careful to not drown the roots. they are being fed straight distilled water with half strength root excelurator, temp is 73-85 55% humidity. the leaves are starting to burn at the edges and are folding up, look like they are drying out a little. 0ppm but im going to stop the root excelurator today. looks like nutrient lockup from pH but i have never added any nutes. leaves look like they are drying out but coco is moist. what the hell am i doing wrong???

I dont grow in coco but have mixed it with soil before. Dose the coco have any nutes in it to begin with, i thought with coco that you had to add nutes from a very early stage although some manufacturers have brands that are pre fertilized. I know this is no help but maybe it will get the ball rolling.

it shouldnt have any nutes. i flushed it with distilled water before i put the seedlings in it to make sure

Dont use distilled water, it messes with the ph. Use either tap or RO

added half tap half distilled ~200ppm but still dont look any better, though its only been a day im just so impatient on what the hell can be going wrong. they are still on their first set of leaves and are looking a little yellow. does ph up or down eventually expire and go toxic? im stumped...i think its still way to early for nutes

I have the same light, your babys are to small to have the light at a few inches above. Try 12 to 16 inches above untill they get a few more sets of leaves then your good to move it back down to a couple inches. Small fan under it works well my 8 tuber puts out a little heat.

I'd have to agree with Mrs.Bush the light is too close, i run a four flourescent t5 unit 2ft long 24w bulbs from lightwave and agree that i cannot get my seedlings much closer than what Mrs.Bush says, t5's are strong lights and do for my whole veg period, give em some room with that light until a few sets of leaves. My lightwave unit gives me very tight nodal space and compact plants.

Id use tap water, works fine for me

the tap water where im from ranks in the top for most polluted- 700ppm out of the tap so i dilute it until ~100-200ppm. took out 2 bulbs of the T5 to drop temps a little and raised the light up. added slight nutrient, not even enough to raise the water 100ppm just in case of nutrient deficiency.

more seedlings appear to be getting these brown spots and patches on them. almost like a 'brown rash' that is covering some of the leaves and the stems are turning purple

talked to one of my friends and he asked if i was overwatering, i said no its damp but theres no runoff- he said to water until there is runoff and get some drip cleaner to wash out any salts that might be in their from when the water evaporates. watered at pH 5.6 100ppm, runoff was 6.0 at 500ppm so im thinking that when i added the pure distilled water the pH might have went way up from not having anything to buffer the pH but im not sure if that will help or not

are you using any type of air circulation?

I would say it looks like some are getting a bit bleached from the light intensity. You might back down off the heat a bit, and let them recover. It appears a bit of the light intensity mixed with heat stress. At this point in my grow I used higher humidity (60-75 percent) and slightly lower temps (70-78 degrees). Also i water once til it drains through then let it dry up.. rinse and repeat in 1-5 days depending on pot size (i use 2-3 gallon early on).

also i was using a mix of peat/perlite at that stage with a ph (i recently realized) of 4, and since i'm using inert medium I added 150ppm nutrient solution to 6.8 tap water (500 ppm out of the tap). My plants now have 3-4 pairs of leaves (plus 1 more if you count cotyledons) on top of smaller leaf growth on all nodes. and are around 4.5-6 inches tall, and they are only 17 days old from the time i dropped a seed.

I'm using a 400watt MH that is 26-30" away from the tops. running temps are now at 68-77 degrees and humidity is 40-50 percent. and my ak47xbubblegum is smelling delicious. and oh yea my lighting cycle is 21/3

idk if that helps but thats my experience and suggestions for your reading pleasure (perhaps)