To me it looks like your pH might be off. Slow/ceased growth is usually a tell-tale sign of a nutrient lock of some sort.

What method are you using to test the pH? If it's a liquid kit, it might be skewed due to particulates in the water sample. Those cheap pH pens that you stick into the soil are notoriously shitty, bluntly put. If you're using one of these methods, I would suggest investing in a nice pH pen (one with an electrode); a little expensive, but pays for itself in the long run.