I know this is a tricky problem to diagnose over the interwebs, but perhaps someone has had similar and has a magic bullet...
I'm on CCR (manual) and when swimming everything seems fine - I'm mostly in caves/mines doing frog/modified frog and keep position above the floor nicely. The problem I seem to be having is that when I stop swimming, for a tie off etc. I find I'm actually slightly positively buoyant...not always, but often enough for it to be a bit puzzling.
Yesterday I spent ages during a dive stopping while swimming to make sure I wasn't positive but then found while swimming I sometimes was heading down towards the floor. Very frustrating.
I've got a couple hundred hours on mccrs, so it's not like it is a new kind of diving. But this drifting upwards I've only really noticed in the last year or so.
Kit has been similar, though I am now on a sidewinder rather than triton and I'm diving a 2mm O3 neoprene suit rather than a trilam. Depths are typically in the 10 -20m range. In the past I have been told I tend to swim a bit head down, but find that if I lift head up etc. I start swimming upwards!!!!
Am I just rubbish and need to practice more or what?