Two plants I really like are Hornwort and Fanwort. They can both float, and Fanwort can also be planted in the substrate but Hornwort can't. You can tie Hornwort to a rock or something that will weigh it on the bottom if you want to, though. I like the way both of them look either floating or anchored to the bottom. I like the look of fanwort a little more- it's more delicate looking. And my fish likes swimming through the floating fanwort because it's less dense.
I found my fanwort at Petsmart, and it was labelled as "bush plant". Either of those plants are great. But if you have a lot of light they will grow super fast and could take over your tank. They're good at absorbing ammonia, too.
Another comment about your well water- I think most things will evaporate from the water if you let it stand overnight, so it should be fine to use without consitioner. Conditioner mainly takes out chlorine and that other similar stuff, but you don't have that in well water. But you could use conditioner just to be safe.