Soil pH is surprisingly high. What's the best/safest way to lower soil pH (without eliminating nutrients from dry amendments)

First, do not overpay for an acid or base to use in this way... It should be cheap... and as long as it doesn't cause a precipitate or otherwise fuck with nutrients, it's going to wrok as well as any other acid/base. People who think the acid you use impacts how much pH can swing or whether it is a temporary change are confused about reality... The reality is, any unbuffered nutrient products will liekly have pH swings -- this is a sign of a shit-ass manufacturer that doens't really know what they are doing, if it occurs.. it is not the fault of the particular acid used. Anything unbuffered will be a risk to swing in pH for absolutely silly reasons that are easily avoidable. If you experience wild pH swings, buy better fertilizer, imho. fwiw, this particular context does not seem to meet that threshold.. this seems like an easy fix. 3 gallon jug of white distilled vinegar is hard to beat, and more uses around house, too. Get some 3mL pipettes for easy measuring. you might need 1-3mL per gallon. (maybe larger pippette or measuring cup, if you deal in larger volumes) Maybe a little extra runoff will speed up the process of shifting the pH, but you don't want to leech your soil of nutrients too much, either... If no major issue, i'd just give enough for a little extra runoff compared to normal and let it glide down to the new pH you target. You don't want sudden, drastic shifts in pH, anyway... Further dialing in ratio and concentration of nutes will probably have a more beneficial impact than the pH. pH is important too, but shifting it a bit wont result in an easily discernable improvement to growth with just your eyes. More light, better ratio/concetration would be teh biggest pieces of the pie - light being 5x more important and nute-related stuff is more about not stepping on our own feet. the spots you see might be from the pH and it might be from ratio/concentration resulting from soil+fertilizer... it'd be folly to assume one and ignore the other possibility.