So I'd like to try and lower the amount of time I spend dealing with watering and fertigation chores by trying to get a bulk mix system in place. I live in the city, small patio, we're renters, no siphons, injectors, Al's rolling cart, etc. I use foliage pro, Protekt and W vinegar to adjust pH. Plants are all in 5-1-1 or gritty type mixes.
I was thinking of getting a food grade blue 55gal drum and keeping it filled with irrigation mix of water, Protekt and vinegar at a low pH of maybe 5.5 or so? The idea being that this is my "base" mix. Then when I want to fertilize (once a week) I just pump it into a container and add a little FP and I'm ready to go.

While I would still need to add FP once a week, I would have irrigation water premixed and ready to use- saving a lot of mixing time as I can often irrigate daily In summer with PT and vinegar. I typically use 15 gal per session so I'll probly empty drum once a week in summer, every two weeks in winter.

Questions-
1- if a drum will likely last only a week or two should I just go ahead and add FP to the drum? I like the idea of constant low feeding even better than weakly weekly feeding, but worried that a standing drum of fertigation mix will be spoiled by algae bloom, where I suspect irrigation mix (just Protekt +vinegar) would not.

2- i wonder if the vinegar would degrade that fast in my drum (1-2 weeks) since it's an organic based acid vs inorganic sulfuric acid? I don't want to debate vinegar vs sulfuric - I'm happy with vinegar. Just worried about how long it lasts in solution so I don't have to keep checking pH. If it's a problem I'll switch to sulfuric.

Any other insights, concerns, tips appreciated.