I am not sure Tami. My tank is not overstocked and I was doing weekly 30% water changes.I have a 40 gallon breeder with 16 red eye tetras,a mollie that thinks he is a red eye tetra, a kribensis, and a clown pleco. Also 3 mystery snails. I use an aquaclear HOB. My nitrates never went above 5, but I was having an algae problem, which is the main reason I decided to add plants. If I am going to grow something, I would rather it not be algae. I just added some amazon swords, wisteria,water sprite, and an annubias. I am fairly new to all if this , so I am trying to figure it all. Sometimes I think I over complicate things