Need Help! First Feeding

Two weeks ago I planted my seedlings into Happy Frog soil, I received my FF nutes two days ago and gave them their first feeding of 1/4 strength Big Bloom and Grow Big. Now two days later my my plants are showing some sort of deficiency or burn.

I'm worried I overfed them too soon, any ideas?

The picture is of my Pineapple express, it is the worst out of the 5.

How old are they? I'm not sure about Happy Frog.. does it nutes in it like Ocean Forest? If so, you probably feed them to early.

So young and asking for Mg? what the hell is wrong with Fox Farm? everybody's having this kind of issue!!

So I'm looking at a Magnesium deficiency then?

Yes, but solution is not always to add more especially at such early stage you should be very wary. I guess growth is stunted now right? how is it evolving?

It does seem to be a tad smaller and weaker looking than the others, what would you recommend? I have to make a stop into the grow shop and pick up a new PH meter as my previous one failed on me. I did check the runoff PH with litmus paper after I watered them and it came out roughly 6.0 - 6.5, using RO and dehumidifier water.

I think it's a bit early for the "bloom"

you over fed them and this is why you're seeing a deficiency. flush them.

asaph is right quick flush people can get crazy with there nutes including myself

Thanks for the advice.

I gave them all a good flush with RO water, when should I start feeding them again?

next watering. just do it very lightly and slowly build up a regimen