Quick release., water soluable notrogen that lowers ph??

Tap water here has a PH of 7.2 - 7.4, my soil has a PH of about 7.5 and my plants have a severe nitrogen deficiency.

I need to give my plants a serious nitrogen boost (water soluble please) as I've just moved them into the flowering light cycle. But I'd like to lower the PH at the same time - is there one product or single combination of products that will do both for me in one swell foop??

They need a FAST boost in nitrogen. I don't care about the "slow release" as this soil is going in the yard as soon as this crop is done and I'll start anew for the next crop.

I'm looking at a product called FLORIN-GRO^TM from Brightwell Aquatics right now, but I've read so much about nitrates, ammoniums and urea nitrogen that I've given myself such a brain lock I that don't find the description on this product (or any others right now) to be overly clear.

Can anyone give me some direction (like a per gal "recipe") as to how to accomplish both of these issues, without burning the plants, at the same time? I don't see a lot of "watering time" left on this miniscule crop and if's there a simple fix... I'm certainly open to suggestions..