I am pretty sure I have fungus gnats in my plants. I am going to stop watering for 3 weeks as it is suggested on many websites. My Cacti have stopped flowering and I am giving them a rest period. After the rest I am going to transplant them. I am going to remove all the old soil and replace it with something more fluffy. The soil that they have gets as hard as a brick when it dries and I do not think this is helping the plants at all. I also noticed that my plants have what I think is shot whole. I posted a link on a garden website and that is what they suggested I look up. This fungus resembles what I have and so I picked off all the leaves that had the problem.