I have been thinking lately. Saltwater tanks have sumps with live rock in it, why not a freshwater tank? I know a lot of these planted tanks have a ton of circulation. What if you were to have a sump with "live rock" of sorts in it? Say, lava rock or texas holey rock or something like that, would it do the same thing? And with that, do you think you could run a refugium with say some stems and moss or something? Does anyone have any experience with this? If you do I would love to hear your take on it and see your setups if you have one.