I too looked at the Pirit; but, I figured I would try the heat tape first ($30 vs $130+). Last nite it dropped to 11 and all is well. I am using a 30' heat tape that covers my 27' hose and filter set-up. The extra 3' of tape i placed on the opposite side of my filter. The whole thing is then wrapped with pipe foam.
As far as the anti-freeze down the tanks, all of my tanks are heated and enclosed. I keep the black valves closed and empty when full. So far, I have been keeping the grey valves open and have yet to notice anything wrong/problematic with doing this.
2015 Seismic 4212 on order
2010.5 Dodge Ram 3500 MC CTD HD Dually (4.10 gears), Firestone Air-Bags, with a Superglide model 4400.
2012 Yamaha Zuma 125