My last try at a nutrient deficiency was with an Archontophoenix. Nothing quite worked and the tree was eventually cut. For whatever reason, others never had problems, though I have a patch in the front yard where both a palm and a cycad seem to have nutrient problems.... Nematodes? I had a bottle of "palm nutrients" from Busy Bee Nursery in Wabasso. Other than that, a good palm fertilizer with micronutrients.