I finally figured out how to grow the aufwuchs at a reasonable rate. I've started a new colony in brine solution that was made up from aged water and mulm from cleaning a cannister filter.
I added some spirulina flake and very quickly got an emerald green emulsion which I assume was some form of algae, possibly spirulina. I then cut up a potato and boiled it in a quart of water rendering it down to cup of milky solution. Once this had cooled I poured it into the algae bath and observed the whole mess getting very cloudy over the next couple of days. After a week, A film about the thickness of an apple skin developed on the sides of the tank and the surface of the bath. Although a darker green, this combination of bacteria and algae mat seems to be equally relished by mbuna fry, as my original batch and under constant light, grows quickly.
The key I'm guessing is providing starches and other polysacharides as food for the bacteria component to feed on. Once they begin to form mats, the filamentous algae begin to grow through out the mat, making it thicker. There is probably some symbiotic relationship as the algae will provide oxygen for the bacteria, who in turn provide structure and nutrients for the algae to grow on.
I know it sounds disgusting but this material is very good live food for young mbuna fry. Its easy to grow and can be frozen between two pices of wax paper.
and Do what you can to imitate the rest of the conditions that were oustide in the summer 
You may not get an answer, but stick around mate, the water is fine! 
