I am setting up a 29 gallon fresh water refugeium for my 300 rift lake tank and am trying to find some good oxygen produceing plants to use to help raise oxygen levels in the main tank .The problem is I dont know many that can handle a ph of 8.4?? I was thinking of using hornwart but you cannot buy it here I dont think But their is a ton of it in a near by lake?? What do you think???What are some other kinds that would do well??