The Cressi MC9 is rated EN250 for cold water diving. Both the Cressi MC9 and Cressi MC9SC are both a class 6 on the EN250 scale. Which means that the environmental seal kit does nothing to prevent a cold water freeze up under the surface. The more metal in your 2nd stage the better. A metal tube in your 2nd stage will increase cold water performance about 22%. An accetal material oriface is better then metal. Scuba-Pro has a silicon bushing for years inside the MK25 that crushes ice off of the S.S. Piston. Also you should turn your adjustment screw in about 1 1/2 turns to increase your breathing effort to about 1.6 inches inhale effort.. Your about to learn more about the physics again. Most cold water free-flows is divers error. We are usually diving 40 degrees avg./100 ft./40 min. The Cressi MC9 is rated EN250. Its all about how much air you are sucking threw the regulator. The cold water is actually warming up that -55 degree air as it passes threw your 1st stage. Your going to have to enjoy the new learning curve ahead of you. And I can put a good bet on it that you’ll have a cold water free-flow. That’s how we all learn. Have Fun !