I've had the same experience with my floaters and it begs the (slightly off-topic) question: could you successfully run a NPT with only floating plants, and no dirt substrate/rooted plants? Or maybe another way of putting it - for someone who has a "traditional" tank with gravel and limited or no live plants, could they achieve some sort of NPT progress w/o redoing their substrate, just by adding floating plants? Or do the floaters not do enough on their own?Robust floating plants like Frogbit and Water Lettuce give you a lot of "bang for your buck." This may explain why my 9 tanks currently have almost no algae, ammonia, nitrates, and nitrite despite heavy fish feeding, no filters, infrequent water changes, and good lighting on 13 hours per day. I have to prune and thin out these floaters once every week or so.