So whats the problem? If you want a plant tank a pH of 7.6 is no big
deal. If your water is hard then find plants that do well in hard water
(Talk to steve in Vancouver about getting some of his illegal Elodea :-).
Seriously, why dont you go to your local building supply dealer? Or find
an aquarium store that sells gravel in bulk. Here in winnipeg we have one
that sells great gravel by the 100 lb bag for reasonable amounts of money.
BTW what is the pH and hardness of your tap water?