I'd say flush them, flush them good, then see what happens. 1gal of water per week, even with good runoff, can allow salts to buildup, especially if you have a strong soil mix. I don't know anything about your soil but if you are only using 1/2 teaspoon of Tiger Bloom every other week, would I be safe to assume you yourself believe you have a strong mix??

Flush them and let them almost dry out. Should show reaction within a few days....

My 2 cents....

CGI::::::
CanGroIt Reviewed by CanGroIt on . 33 days into flowering, strange spots. nute burn or possible deficiency? Pic's. Hey folks, I just noticed these spots today on BOTH plants. They are mostly on the top fan leaves. I had problems earlier in this grow, corrected it and for the last 5 weeks things have been going good until now. Here is some more info and pics. What is your experience level? (first timer, novice, experienced...) Novice. Been at it for a few years. Your Equipment: .1) Type and wattage of lights. 90 watt LED + 2 x 42 watt cfl .2) Distance from tops? A few inches Rating: 5