White Gummy

Could be it wants a bit more nitrogen. Your balance is 4-4-4 so you could use a calmag nutrient with more nitrogen in, a lot of cal mag products have 2-0-0

Definitely looks like under watering to me. Make sure to water wide and deep and to run off every few days and wait until the top inch or so is dry before watering again. If the soil has become overly dry, you may need to repeated the watering 2 or 3 times initially, to fully moisten in the entire bucket, from top to bottom and from side to side. Wait half an hour between waterings if you do need to rehydrate your container, this allows the soil to swell a bit between applications and helps to prevent the water from flowing straight through without being effectively absorbed. Cheers, Organoman.