Careful with the dipping and overreaction. I don't see anything that looks like AEFW and I don't see any specific damage that looks like AEFW. Dipping a stressed acro will solve the problem for you by killing it. If you feel the need to dip use Bayer, otherwise just keep an eye on them for the telltale circular bite marks. The fact you have tip burn and recession, plus a birdsnest showing damage points to a water quality issue. In my opinion, of course. 
