I agree with switching early to bloom food will cause problems. I just chopped a plant that didn't have a yellow leaf one.
You will be better off sticking to a balanced feed. Dynagro is good stuff and cheap. On their website you get a quart of foilage pro, quart of protekt, pint of bloom, pint of kln root solution for $19.
That will last quite a few grows. The foilage pro calls for lime 5 ml a gallon but it still works great at 1-2 ml a gallon.
Also flushing without knowing why is a bad idea. It strips the things that regulate pH.
Proper watering technique, or lack of, is also part of your problem.
Keep it simple. Balanced feed, 5-5-5 10-10-10 or something lime that. If a number is off one or two that's fine. Balanced feed from start to finish.
When you use synthetics make sure to get 20% run off from the bottom of the pots to prevent salt buildup.
Water when the pot is light. Let it dry. It encourages root growth.
Keep it simple. The more you love it, the more you kill it.
Oh, and cannabis specific nutes and potions and what not are a gimmick.