My out the tap pH is about 7.4 to 7.6 depending on how much it's rained. I live on the edge of mountains comprised of ancient shield material so it has almost zero calcium content. Water pretty much rains down, flows downhill into a standing resevoir and into my tap - they also add almost no chlorine unless there's been a dry spell, when Gh also goes up a notch. But kH is always zero, even when they tried to add it to the entire water supply by filtering thro' limestone chips.
I've also a belief in excess protein and general bad care causing bloat in tropheus and mbuna, but I also have a 'bad feeling' about piling in the NaCl. It can't just be protein - for sure many mbuna get bloat, but they're not all obligatory herbivores - animal matter makes up a varying proportion of their diet. For sure poor water conditions will hurt them and weaken them, but mybe adding salt and causing osmotic problems is the 'straw that breaks the camels back'. It's anecdotal, but when I go to shops, auctions and wahtever locally and talk to people bloat doesn't ever seem to be mentioned, and maybe one of the causes is we get different brands of pH, hardness adjustors here.
What about water chemistry - well tropheus are farmed in florida I believe - has anyone ben to, work at or own a farm - what are the water parameters - not the 'ideal tanganikiyan' I would suspect. Agreed, a topic for a new thread....