ginti
Contributor
I've seen quite a number of divers who were a bit "gun ho" get in trouble in tropical water or Meditteranean. These were guys used to cold water (in winter 3-4°C / 37°F), low vis and even current (tidal waters, shore entries). How do I know, because I was one of them (starting diving in the North Sea). This is 20 years ago and I've progressed a lot as a diver, but even now when I'm diving with a dive OP, in a spot I've never been, I'll pay attention and have a healthy respect for their opinion, yes even super easy 20m depth recreational dives. Because THEY are the experts in their water, or at least until proven different.
Same happened to me. I was used to cold murky quarry/lakes, and I developed the habit to use the lake morphology as a reference; meaning that, if I got slightly far from the bottom (or the rock wall, if this is where I was diving) I immediately could recognize it and go back to a good position, because I couldn't see my reference well enough any more.
When I first went to the sea after a very long time, I started using the morphology as my reference; small issue: you can get 20m far from the bottom and still see it perfectly... so my reference was just a bad one. I ended up yo-yoing a lot without even realizing it (only feeling in my ears stopped me from doing crazy things).
Cold water with low visibility is just a different environment with different characteristics