Hello MP.
Been a while
I've been growing organic for a few years and have to confess that i am a long way from where i would like to be !
In saying that i used to use Fish emulsion and liquid kelp/seaweed as my main feeding regime along with Various organic soils and organic pellets to act as slow release biscuits kinda thing with azomite, kelp meal, dol lime,worm castings , and even compost to create my soil !
I always Ph checked my feeding schedule purely to suit the plants comfort zone Ph6.5 i never tried feeding at the Ph10.2 readings so i'm not sure there !
Now i use worm tea in conjunction with compost tea and i was ph checking it until about 10 days ago but i no longer check Ph now because Hushpuppy offered some good advice in a thread and my plants are still happy without adjustment the microbes that are brewed do all of the work to ensure the rootzone is Happy "so to speak" !
I also used vinegar a few years ago but found that concentrted lemon juice was cheaper and more so closer to being organic both worked well in my opinion
Some would also say that food products are not suitable to use as ph down because it will tend to raise pretty quickly ...But for me i had no problems whatsoever JMO
You might find some useful info in my greenhouse grow pcduck has helped me get most of it on cue but there might be a few extra tips/ideas of interest.
Good luck MP
THC.