I highly doubt there is a problem with the Controsoil, you said you calibrated your pH pen recently? What process did you use to calibrate it and how have you been storing it?
I had very expensive sensitive shrimp delivered this past February daytime high was 14F all survived and were fine. Cold weather is actually better since the shrimp metabolism slows down. Their respiration slows along with waste production.
Properly acclimated shrimp should land after putting them In and just eat where they are. Any swimming around I see as stress. I always drip for 2-4 hours depending on how different the water is. Hopefully you have some luck since tap water is very unpredictable.
Different water remineralizers have different components that can react with each other negatively or overdose on elements that are required in small amounts.
It is odd that you would have nitrites on day 3 without adding bacteria. But the cycle usually goes that ammonia disappears as nitrites rise to a high level then disappear overnight. Cranking up the temperature also helps the cycle go faster.
I would recommend a BRS4 as entry level from Bulk Reef Supply, this is the unit I use and absolutely love it.
http://www.bulkreefsupply.com/brs-4-stage-value-ro-di-system-75gpd-2.html