I hate to be contradictory here, but the problem is low fert, not overfert. According to your info, you're feeding fert about every 8-12 days which may not be enough depending on how much you're giving. Also I don't think the 2 of 2-3-1 is enough at this stage of growth. I think I'd try giving a double dose at next water of that fert. Adding ferts during a grow makes for alot of guessing that doesn't need to happen. Powder ferts that come in a box are the answer.