Looks like you are using different mediums. What are they? What are you feeding them and did you do anything different than usual? Your plants look a tad yellow. I believe you are using MC V2. Check your pH of soil and of your mix. Make sure you don't have any pests. My buddy struggled with MC V2, had pale plants. But he also had gnats. He is using AN now and his plants are doing much better. His gnats are almost gone he said. I really liked MC V1. It smelled bad, but worked great. Personally I think V2 is inconsistent, and way different than V1. The calcium chunks in V2 make it hard to have equal feedings in small doses. I would like to recommend Green Planet nutes if you continue to have issues. I ran out of MC and moved to Green Planet. My plants love it. I love it. Way easy to mix and the plants are doing better than with MC V1 and V2. They look extremely happy. I use 2g per gal of Calmag pro. Then 6-8ml per gal of Dual Fuel. It isn't expensive, you may want to give it a try if you keep having pale growth. Just wanted to let you know about the Green Planet nutes, I can't say enough about them. I actually like the Calmag pro from Greenleaf. I have a ton of it. So I use it first then 6-8 ml per gal of Dual Fuel. Perfect for veg. Add a few ml per gal of MASSIVE, Rezin and Liquid Weight in flower and use 6ml.per gal of Part 1 and 2 each.