Energy require to convert saline water to fresh water for a range of salinity and recovery levels. 1 kJ/kg (1.05 kWh/kgal). Seawater is 3.5% dissolved salts by weight.
I'm type 1 diabetic, always had problems w prednisone raising my blood sugar. I was just prescribed 20 mg a day for 7 days for a SLE flare up. I can't believe this, I'm having quite a few lows! It was interesting to see someone else have the same.
But 208 is a very high blood sugar. Prednisone definitely will cause elevations of blood sugar, but you need to be evaluated. Having your height and weight would be useful also to estimate your diabetes risk. I would eliminate all sweets and recheck blood sugar.