Yeah I think part of ur problem in ur soil is the 1/3 peat moss, if I remember correctly peat moss can be very acidic so you don't wanna overdo it, and u can always go buy one of those cheapo 3-way meters for water, light, and ph. The ph one usually breaks 1st and isn't very accurate but it sounds like u were havin some overwatering issues, so u could use that to get an idea when ur plant needs water. Just gotta remember it can be more harmful to over water ur plant than underwater it cause u can't take the water out, its kinda like cooking a sauce u don't pour in all the spices at once cause u can't take em out after, but with ur plant its always easy to give it water if u see it needs it.