What is your Salinity? -Reef Tanks

[Noj]

Just wondering, to anyone who knows...why is the SG at 1.025+ prefered?

I'm a fisherman and whenever we have to deliver our product alive, we keep the SG between 1.019-1.021. We dont keep it lower to save on money because we use different salt than aquariums. Our prawns have no problem in the tanks and can live in a plastic fish tote (equivalent of about a 65G tank) for 40+ hours with 150-190lbs of prawns inside. The SG levels and temperature are dictated by the company that buys the prawns because those are the perameters of their tanks.

When we measure the SG of the ocean water (taken from approximately 15 feet down) it reads around 1.015-1.018, depending on location of course.

Any explanation or ideas? I'm sure its something simple and i'm just overlooking something obvious.


-Cam