I keep getting a few small patches of BBA on a piece of driftwood every now and again but changed a few things after some advice on here and it started to go.A spot of BBA around 6/7cm in length came back over a few days but then this morning there is a tiny piece around 1cm left.it has just gone.thing is, I've not done anything to it .Does it just disappeared or slowly die off? I have Amanos and nerites in the tank , could these if taken care of it?