Background info: First time growing some bagseed indoors using 3 gallon plastic pots, Black Gold soil. I have two- 2ft 4 tube T5 grow lights + one extra seedling starter light. Bulbs are 24watts or so and I am using a mixture of the warm red spectrum lights for flowering. Started grow early May. Switched to 12/12 lighting schedule 4 weeks ago. Nutrients fox farms big bloom and tiger bloom + a Cal-Mag supplement. General hydroponics vial pH test indicates an ideal pH range of 6-7. I just use tap water from the sink. For the most part, I've had little to no problems during vegetation. But 4th week into flowering and I believe my plants are suffering heavily and I have no idea what to do. I think I may have been overwatering/feeding. I know for a fact I burned the tips of the leaves when I thought I had a Calcium deficiency. I was using fox farms big bloom 2tbsp per gallon of tap water and giving a quart of water to each plant. I read the chlorine in the tap might be an issue? But I adjusted with some pH down and made sure the range was ideal. Eventually, I noticed leaves dying like crazy, turning yellow, brown spots arising, stems turning red, and leaves curling. So, I flushed the soil with neutral water, assumed maybe Nitrogen or Phosphorus deficiency and switched to Tiger Bloom instead. Its been a few days since and the plants look a little more green, but now I have bigger brown spots at the top of the plant instead of the bottom. I'm a beginner and I've made some mistakes but I really don't want to lose my plants.