I think I'd look around at the ponds in your area that have good submerged vegetation, see what species that is, or just pull some out of those ponds. Should be good for your area and probably free. Some folks may even thank you for doing it. Caution: certain species in certain areas are considered invasives, so that may or may not be an issue. If you just want plants, invasives may be the way to go since they will grow well!

Mark