The problem is that your tips are burning and your leaves expecially the shoots are yellowing. The shoots are where the main concentration of growth cells and hormones such as auxins are found. Superthrive is a hormone additive and not a fertilizer. If you have been using more then one to two drops per gallon I would stop using it all together as auxins can lock up. Tips burn and leaves curl do to high tds (total dissolved solids) of ions in the medium deposited by the nutes at a level the roots can not keep up in processing. Once they reach a certain level they become toxic to the plant and the plant will not absorb them as starving itself is healthier then uptaking poison. Yellowing of the leaves is usually caused by a low ph due to a high tds and soil that is to wet on the bottom of the pot. If oxygen can not penetrate the soil every 3 to 5 days the micro organisms which play a vital role in the uptake and breakdown of the nutes begin to sufficate. This is why it is best to keep so humid to damp. Ammonium nitrogen for example must be broken down by micro organisms found in the soil zone as well as rhizosphere converting it to nitrate before it is even usable to the plants.

So what to do. I would flush the one gallon with three gallons of water and up the transpiration of the plant to clear the excess junk stored in her viens. Heat of 85 to 90 degrees with dry air will help. The soil would ideally need to dry out in three days. Bone dry about. I would use my finger and make a tunnel in the form of a cross on the bottom of the pots to ad in the drying and make use of a fan.

Added health can be obtained with CO2 use which can be made with a gallon jug 3/4th gallon of water or less, and a table spoon of active yeast found by the cheese in the grocery store mixed with hot water to dissolve it. Poke a hole in the top and shake twice a day.

I would cut the fertilizer level in half aswell.

Hope this helps

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c