Natural ways of lowering PH. Help!

hey all, im trying to find the best organic way of dropping my soil ph a bit. I'm in 5 gallon buckets and my ph spiked to 7's and hasn't budged, not sure why. Anyway, I've read about using brewed black coffee (cold) as a way to quickly drop the ph of soil, is there any truth to this? & if so how much would I use to a gallon of water?


Promix HP:
General Organics nutes:
600w HPS:

Soil was mixed with a tbsp. of dolomite lime per gallon.
Mykos in the transplant holes when I up potted to 5 gal.

Any help is appreciated as im starting to see some deficiencies and I just flipped to flower 3 days ago.

You should not be seeing a ph lockout if it is 7. How do you know your ph is out of range?

Pics?

how are you measuring the ph of your soil? you can't just measure runoff and get any meaningful information without some research first. you have to do a slurry test, and know what the numbers actually mean. you cannot expect run off to be the same ph as the feed you put in. as the plants absorb varying amounts of nutrients from the solution, the ph will rise or drop accordingly. if you are getting the same out as you're putting in, then you have a problem, because your plants aren't eating.

general hydroponics ph up is potassium carbonate and potassium hydroxide....nutrients....
general hydroponics ph down is phosphoric acid and mono ammonium phosphate....nutrients...
no weird shit to sit in your medium and fester and promote pathogen growth....coffee has fats and esters to spoil and grow nasty shit...vinegar is the same, and will grow a nasty mass called mother of vinegar....just use ph up and down...IF...IF you need to make adjustments at all