I have a Lake Tanganyika tank set up with Altolamprologus compressiceps, brevis and Cyprichromis Leptosoma. I would like to place some floating plants in the 2 back corners (think riccia fluitans or java moss) but I don't want them getting caught in the filtrations system or in areas of the tank where I do not want them so I would like to attach them to something that floats and I can tie with fishing line in the corners or I'd like to corral the plants somehow. I have heard of people doing this in tanks with cork bark but I am also worried that this may lower the pH and hardness or be otherwise dangerous for Rift Lake cichlids. I do have the African cichlid substrate from Carib Sea as well as naturally very hard water from my faucets so I don't know if it makes a big difference. Any opinions on cork bark or other ways to have floating plants in one place? Thanks.