Most LFS's carry Flourite. Your regular gravel will grow plants just fine, though. As a matter of fact, some plants don't care what substrate you have, since they are water-column feeders. Hygrophilia, Rotala, Egeria, Ludwigia, Bacopa, Hornwort, Wisteria, etc. are all primarily stem feeders. Their roots main function is to anchor them in place.
If you do have the opportunity to completely tear down the tank (no fish yet), then go for it. If I had no fish in my tank with a 2/3 Flourite / 1/3 gravel mix, I would do an inch of kitty litter first, followed by Flourite, and topped with an inch of regular Home Depot Play Sand.
But if your tank has fish and is well established, and your gravel is smaller than 2-3 mm in size, I wouldn't worry too much about tearing it all down. Even root feeders like Echinodorus can do well in a sterile gravel substrate with supplements like Tetra Initial Stick (or Root Tabs) and some Jobe's Sticks.
- Sam P -
plantedtanker in limbo - all tanks currently in storage