Ugh I had this problem for about 8 months. Not that high but the under feeding and still just going up and up. I wish I could tell you what worked but I eventually just threw everything at it. Huge Refugium, nopox, under feeding, pods,reef mat, change of foods, skimmer, lots of CUC. It eventually just turned into a GHA forest!! I guess Nopox was my last resort as I hate chemicals but that was the only thing that started to turn it around. But I haven’t been able to stop dosing it so whatever it is problem isn’t solved just bandaid. If you figure out the answer I would love to hear it!!