He wasn't suggesting to bring the pH down at all... your plants just look deficient and in soil, a too acidic pH could cause problems with the Ca/Mg uptake. But it could as well be that your soil is leeched empty and you need to feed (always feed @ pH 6.5 in soil)
I'd apply a strong foliar feed with Epsom Salt, chelated Fe & Urea. And in the interim take a slurry probe to check EC & pH of your soil and then go from there. No clue how high you did charge the EC but just add 30% more of a full veg formulae fertilizer, or some specialized "green"-supports like CMX.
Or you find your pH is out of whack - then you just need to counterfeed and wait for the plant to sort this out.
A few humic acids may also help in nutrient intake.