I've been growing my fine, but quite plentiful hair for a year or two and find that it's getting really knotty and in some parts matted together! If I've worn a bobble hat it gets difficult to brush afterwards... I often run or bike.... helmet hair! And it's becoming so tangled. I wear it in a plait at bedtime..but as I've never really had long hair before l don't know if there is a serum or something to make it silky smooth.!? My 50 plus hair isn't what it used to be....any advice...please.