I have a 5.5 gallon tank with the finnex stingray clip light (4 watts). I am pushing limits of stocking capacity (so water has nutrients from fish in it). I have two anubias right now (nana and petco assorted). There is slow but noticeable growth over a week or so period. Have minor algae on glass. I don't remove it until it becomes a visual problem. Also my watt per glass is about 0.72. Which is a little low. Not planning on getting any more plants besides maybe some water wisteria. My question becomes can/should I use some sort of fertilizer. On requirement is that it's under $10 and easy to use.