Fix your runoff according to the sticky at the top of this section. That will prevent further problems. But this is the most bizarre statement in this thread:

Quote Originally Posted by dillhole
I also gave a light foliar feed of H2SO4, thinking the yellowing looked similar to Mg deficiency.
Okay, where to begin. H2SO4 is a STRONG acid! Unless you have sulfuric acid at your house, I have to assume you got it from your bottle of pH down liquid. Never ever under any circumstances foliar feed your plants with pH down. Next, I see no Mg in the molecular formula for sulfuric acid, so I'm not following your logic as to why you'd choose H2SO4 over MgSO4, whcih actually HAS the Magnesium ion available... ? Finally, that's not mag def.