Yo, I'm assuming the one with browning is the Happy Frog?????? I've always stuck with Black Gold as it's pretty plain and I can add my own mixture and not worry about excessive nutes. As a matter of fact as of now I'm running an experimental grow with a few different strains from NIRVANA in Ocean Forest, Happy frog and black gold with same added nutes and I can easily see the Happy Frog ladys burning up so I cut down on nutes. Happy Frog did great for clones and seeds. Never mind I see you mixed 50/50, I wouldn't do that due to difference in NPK content of the 2 soils and making it confusing to know what you really got. If you have a PPm meter measure the PPM of the run off and make sure it's not too high, looks like nute burn. Also B carefull with epsom salt, usually not needed as much if any, you soil will get too heavy(mineral wise). Flush FLush Flush if PPm high. Some good RO water or even distilled water