You don't need to water until the soil is almost dry. Pick up the pot before you water and you'll get a feel for when it needs water by the weight of the container. You're probably overwatering. You need to use a bloom nutrient that is a stand alone. Pure blend Pro bloom for soil is a good choice. Use Big Bud through the whole bloom cycle. 1/4 strength is enough.

You need to exhaust some air at night or the humidity may rise too high and promote bud rot. If you don't have one, get a digital thermometer that reads humidity too.