My 60g is a planted display tank and all my tanks have floating water sprite and some (never ending) duckweed. I had been adding Flourish Comprehensive (a bit less than directions) and the water sprite grew like weeds. I stopped fertilizing and for months, the plants continued to grow well. Then suddenly, the plants began to fail. Almost unnoticeable at first, then as though they were on their last legs (or roots as the case might be). I guess in time, they slowly used up the nutrients they needed. So I began fertilizing again and the plants are coming back really well. In hind sight, I'm surprised the plants didn't begin to fail sooner - it may very well be that even though I was fertilizing less than recommended, that was actually slightly over fertilizing. I'm thinking just maybe half or a quarter of the recommended amount might be the right amount.