Hi guys. I am starting to get more into the planted side of the hobby and I am still very new to it all. I have had a tank setup for a few months and it has been doing well so far. It seemed to have happened almost over night. I did a PWC and added some epsom salt 1 tsp to a 18.5g tank as my betta was bloated (he is doing well now). I have seachem root tabs and i have a 24w LED full spectrum light. The tank has a decent number of fish but never much nitrates, around 5ppm at most. Temp is around 77f. Here is a picture, if somebody could tell me what causes this or needs more information just let me know. The rest of the plants are doing ok Val is growing like a weed, the Anubias is looking good. Thanks for any help it is always appreciated.