From the Vortech users manual, "Soaking these parts in a mild acid solution such as vinegar may be necessary if there is an extreme amount of calcium buildup."
The Magi-klean product is phosphoric acid. It's actually stronger acid than vinegar.
Do you have a calcium buildup? It will be white and hard. You might have lots of coraline algae. Also hard but usually pink.
Since this is Wine country, I recommend red wine vinegar! Just kidding. Just get the cheapest white vinegar. You can dilute it 50:50 if you want. It will take longer to work.
Full strength should take an hour or so to clean it up. Stir the container every so often to get fresh vinegar to the crud. Toothbrush or aquarium brush to help it along.
Rinse well afterward.