I have my 15 gallon fish tank for a good year with 2 goldfish in it and throughout the year I haven't seen any algae of any sort inside the tank. I don't turn the fluorescent lamp (15 watts) that long - 2 hours a day. The tank is not exposed to any light because there are no windows were I have my fish tank. The water temperature is always between 68 - 80 degrees. I have the tank filtered with a 30 gallon filter and I do regular water changes of approximately 20-30% every week.
The problem is that I got a couple of plants (a week ago) for the tank because I decided to have some plants. I got some anacharis and since then I have been turning on the fluorescent lamp for 10-14 hours each day. The plants don't seen to grow any bigger or look healthy either. Some leaves are yellowish, some are bitten by my goldfish and others just fall right off the stem. So I was wondering if it was my tank's fault that the plants aren't growing because in the past it couldn't support the growth of algae.
I bought fertilizer (Plant Gro) yesterday and poured a couple of drops inside the tank but I still don't see any difference in the plants or any signs of algae growth.
Maybe my fluorescent lamp isn't strong enough or maybe my plants need more carbon dioxide. I don't think it's a matter of the nutrients that are inside the tank because goldfish produce a lot of wastes that are useful for my plants plus I added fertilizer.
Another question. Since I'm using fertilizer, should I take the carbon out of my filter. I have a whisper filter. The one's you hang on the back of the tank.
Yesterday I also took a couple of anacharis in a separate plastic tank that I have and I let it sit near the window where there is light with some gravel from my tank, water and some drops of the fertilizer. Unfortunately, it has been raining these past days and there is no direct sunlight.
Thanks for looking at my post and hope you can help me.