Mag Def? Or Nute burn

[Jaycewin]

Hydro flood and drain buckets with hydroton. Rockwool starters but it's laying above water line.
Flooding 3x a day
Week 2 veg
500ppm.megacrop
Running sterile so just a tiny bit of bleach
Temps 79 to 84(I know it's hot but not the problem for this case)
Ph 5.8 to 6.0
Qb hlg600 lighting 36" from canopy

Can anyone point me in the right direction? I thought it was mag Def so I upped the ppms to 750 but it seemed to get even worse? So now I am dropping it back to 600.

I don't think it's light burn cause it's middle leaves affected.. Bottom leaves are a little yellow.
These are transplanted a week and a half ago.

 

[Anthem]

NOT burn. Some def.

 

[Jaycewin]

Ugh.. One room had same problem too and I boosted it up to 750ppm and that room was even worse than this. I definitely think nute burn too but raising ppms made it worse? Should I raise ph to 6.0 and hope they can take in mag easier?

 

[Beachwalker]

pH fluctuation

 

[AnselAdams]

Ugh.. One room had same problem too and I boosted it up to 750ppm and that room was even worse than this. I definitely think nute burn too but raising ppms made it worse? Should I raise ph to 6.0 and hope they can take in mag easier?

Maybe this can help with your nute vs PH issues. I think @Beachwalker prrovided a very pointed clue. Some research may be in order.
Tthis may help.