Molasses is very good if you can get it working right.
The potential problems I see with it are:
-You bought molasses that contained sulfur, rather than unsulfured/blackstrap.
-You added too much- Generally you will see results at the 1/2 tablespoon per gallon of reservoir level. With molasses, you don't add sugar as well, but you may use a carb synthesizer like Sweet or TopMax to increase effectiveness.
-Another problem with adding too much is the amount of iron in molasses. Overdoing it can lock out other nutes.
-This one I am not sure how it would happen, but interaction with another nutrient component isn't out of the question, although I've never heard reservoir sludge described as 'soap'. It usually looks like a dark olive-green to brown thick, slimy, mass that will clog pumps but rinses off easily.
I noticed the trim work on the doors- cool. Are you a carpenter by any chance?