Hey Rootyb,
You've been a forum member since last year so hopefully you've gotten to know that we're pretty much advocates of a do-it-yourself approach to pool water chemistry and maintenance. Sounds to me like your pool-guy wasn't doing much or maybe too much....hard to know without any test results. If he was using cal-hypo shock a lot, then he may have loaded your water up with calcium. Typically a thick water-line calcium scale is indicative of major chemistry imbalance. Considering you've also reported algae growth during the cold winter months (when algae reproduction rates are so low that they become insignificant), it sounds to me like your pool-guy did a lousy job of keeping your pool clean.
Our advice comes with a string attached - you have to get your own test kit (one of the ones we recommend on the forum here), test your water yourself and post results. You can even take a picture of the scaling you are seeing and attach that to your post as well. Then, you will find that we are happy to reply with suggestions.
As for the auto-fill, well, allowing water to continuously evaporate off and then re-fill can leave a calcium stain which is why it is better to leave an autofill on so that the water level does not drastically change. But your water-line calcium scale sounds more excessive than that. Post results and we'll be happy to help.
Good luck,
Matt