
Neutrog is also around the corner from here, maybe I can score a job there one day.
Hint for anyone organising meetings, some reps are wonderful at bringing along free samples. This lady brought sample bags of products for every member, as well as the large bags which were given to those who could answer questions after her talk.
With salt buildup and rainwater vs mains, my comments - rainwater will be far better than mains, other sources eg borewater be wary of salt content. With saltier water, you need to use an excess to flush away salt buildup. The rule of thumb given by my hort professor was 10% more than the holding capacity of the pot, holding capacity meaning the mix is thoroughly soaked, none draining out. For irrigation in fields excess water needs to be given to keep the salts moving down into the subsoil too. One of the reasons a good soak one a week for outdoor plants is better than a sprinkle a day.
The only advantage to mains water is that being chlorinated and so more sterile, it has less tendency to lead to fungal diseases, 'damping off' of seedlings, and those kinds of problems. Might be better to use for any superhumid areas where you are trying to germinate seed or strike cuttings. I don't have a choice, only have rainwater available, but I leave my seeds/cuttings in the open to compensate.
A 'tea' made by stewing wormwood in water for half an hour or so is meant to be the 'herbal way' of counteracting damping off, I have tried it with no particularly outstanding results, though it did make the house smell interesting..