What do you mean with storks Stinky?
Don't understand and don't wanna do something stupid.

That said.
You can even go lower than that with benefits concerning pH.

5.6-5.8 seems to be on target.
Water often, in fact you can't overwater as long as the pots are drained its fine. I water mine to runoff every 12-18 hours. Hard on nutes.
I use Hesi Coco line and was up on 100% strength when they were 18 days old and still no burning. I went to 150% with vegg nutes and started bloom nutes on 150% and went to 175% very fast. Now I am going 200%.

Now natrually you need to keep ppm monitored as different lines have different built in concentrations. But they should be able to take 1000 ppm after 3 weeks (from seed) and from there you can go up to 1600-1700 gradually over the coming weeks.

I clone straight into coco as well, no cubes. Works as a charm. I just water through the coco completelly with 300% Root Complex (Hesi) pH corrected and plant the clones freshly cut with some rooting hormones on the stems.

If your pH was between 5.3 and 6.5 it wont be a pH issue you have exeprienced. You wont have a problem using MH either as long as temp is fine you wont burn them with light. That leaves 2 likelly reasons just as stated here.
Under nuted/overnuted or genetics. (Yes you can under nute seedlings in coco)
As Stinky sais seedlings wont look perfect all the time always. Just look at mine early in the log and they turned out fine. They were so sick.
Control every parameter that you can and if those checks out fine just let them grow. As long as they grow nicelly they will bounce back from flaws and turn out fine.
The third possibility would be disease/pests but I hold that as unlikelly in this case.

If you get unexplained problems flush them with pH corrected water and then directly after add the nuted mix pH corrected and checked for correct ppm. Normally that will help. Coco grows reacts very fast.

Puffzter