I have a 29 gallon, semi-planted, freshwater tank. Already cycled and been up since May. I was using ML Special Blend until a couple weeks ago and didn't notice anything strange with test results until today, nitrate was 0 (3 times, API Master Freshwater). I haven't added anything since then and have done 2 water changes (20%). I've been looking all over for what a nitrate level of 0 means and the closest thing to an answer I can find is that the closer to 0 the better. All I can think of is that the plants in the tank are absorbing it all, but I still have algae growing... Anyone have any ideas on why it's 0? I'm assuming this is great for the fish, but is there reason for worry?