I'm thinking that your pH-ing didn't 'take' and that you have a serious pH problem. I've seen that before. What is the sand? Does it have limestone in it? Did it have a reddish tint indicating high iron? Minerals in your soil are BAD because they make it really tough to feed properly or keep the pH stable. You need to use totally chemically inert agents like perlite to make the soil more friable wihtout adding minerals by mistake. I'd take that sucker right out of its current pot and shake off the rootball just a bit, and repot it into KNOWN good soil, and then give it a nice drench with water at pH 6.8.