Mark, I have not talked to anyone else about the Hiatt system, it seems to be working very well for me.  But you know me, I like to play around with stuff.  I am guessing my system is just fine with the alkalinity at 10 dhk, and the pH at 8.0.

Here are some pics of the surface of my tank, and sump.  I know the sump could use a little more agitation, one of my pumps died (although I didn't notice any pH change by loosing the pump).

 

As I recall, pulling outside air through your skimmer was not extremely effective at elevating the pH and was not a solution for this "winter" pH problem.  Although it couldn't hurt, I don't think it would solve your problem.  A large portion of the gas exchange occurs at the surface and not through contact with your skimmer bubbles.

 

I think to elevate the pH without the use of kalkwasser (to avoid raising alk) you're going to need to improve the ventilation and possibly brave some cold by cracking a window!

Also, with huge amounts of macro algae, do you still need the high alkalinity to get the pH up, or does that use up the CO2 enough to maintain a pH of 8.2 with an alkalinity of 7?  I know that would not be an option with my setup, because I don't think I have the nutrients to support large amounts of macro algae, but I am curious to know if that would work.