What kind of bottled water, and why? Are you adding a calcium suppliment?
Might just need a flush (with properly ph'd water) and some calcium. Ph is a very important number to know. Would find a way to figure yours out, with either a ph pen, or those freshwater aquarium ph test kits. (won't help with run-off ph, but is still good to know tap ph.

Would adjust your nutrients a tad. I've used the FF 3-part for years, so can offer a little advise...do you have the FF feeding schedule from their website?

If you look at their schedule, it tells you how much to use per week. I cut the dilutions in half, and feed twice weekly. (adds-up to the same weekly totals) Please note, that I cut the Big Bloom quantity in half. (one quarter strength, twice per week) Ya just don't need as much as FF says, lol.


Might be easier to show an example of what I do for flowering:

Transplant and switch to 12/12.

Weeks 1 thru 4:
Monday - add 1 quart plain ph'd water to the plant. (if larger than a 3 gallon pot, ok to add 2 quarts) While waiting for it to soak-in, mix 1/2 dilution of the Tiger Bloom, and 1/4 the dilution of Big Bloom. Add to plants till slight run-off. Try and remember how much it took to run-off. Comes in handy, as you can gauge how much you'll need to mix, in the future.
Thursday - 1 quart plain ph'd water to the plant. While waiting for it to soak-in, mix 1/2 dilution of the Tiger Bloom, and 1/4 the dilution of Big Bloom. Add to plants till slight run-off. (no need for additional micronutes, as the Fox Farm nutes already have 'em)

Week 5 to finish:
Monday - add 1 quart plain ph'd water, Mix 1/2 dilution of the Tiger Bloom, and 1/4 the dilution of Big Bloom. 1/4 the indicated mix of Cha-Ching. (1/8th tsp per week, is what I give...I think. If otherwise, I'll come back and correct) Small dollop of molasses, a dash of Botanicare Sweet. Add to plants till slight run-off.
Thursday - 1 quart plain water, Mix 1/2 dilution of the Tiger Bloom, and 1/4 the dilution of Big Bloom. Add to plants till slight run-off.

Monthly, on a feeding day:
Flush with at least one to two times the pot's volume with ph'd water, to help release the salts Fox Farms is famous for. Add nutrient solution as usual, in the last 1/2 gallon or so.

3 or 4 days before harvest...flush well, no more nutes till harvest.

For veg...I follow the same basic break-down for feedings, and monthly flushes to release the salt build-up.
One quarter strength feedings for rooted clones and established seedlings.