Minimum rule of thumb for me is 30 watts per square foot. Also If you regenerate your plants the life span is elongated. Leave a few buds on a plant after harvest under long hour light patterns, and a few weeks later the plant will start to veg again. With the root ball and base plant grown...
I really think the water needs to be flushed well. Place that PH at a set spot. Like 5.7 is great. Plus I have seen over watering on times lead to stunted yeallow in every leaf tip. Maby even a weak branch or 2 also?