Chief, that cold water is from a halocline (that is a fresh water spring mixing with salt) and coming out of springs from the interior of the island. They are more common after heavy rains, but happen all year long. When the water is very warm I look for them to cool off!
Dave Dillehay
Aldora Divers
PS I have frequently been "stung" by invisible floating hydroids at the safety stop, indeed, that is the most common place.
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Yea you already educated me a while ago on the cause of the halocline. I just don't remember experiencing it that often. Had some surface run off at paradise in September, but these this week were fairly consistent, at depth and for the greater part of the dive.
On the floating hydroids: I thought a lot of that was stinging from that thimble jelly / sea lice / jelly fish stuff? Or are some of them technically hydroids? I guess maybe my idea of hydroids is too narrow? I think mainly of the fern-like bits that surround things that would make a good picture?
Thankfully, I think my repeated hydroid photog hits have let me develop a bit of an immunity. I was showing a goldentail in a hole to some new divers when someone body checked me into a GIANT hydroid colony. Beautiful welts came up, but it *looks* like it is mostly gone now.