Join Date: Apr 2009
Location: Amherst, NS Canada
A couple of observations which you can feel free to ignore, some may not "agree" with a lot of people believe to be true.
A.) New planted tanks (especially set up by people with limited experience) tend to go through waves of algae infestations. These have a tendency to straighten themselves out. The kicker is people are doing all kinds of weird and wonderful things to their tanks at the time (to rid themselves of their problems). Fertilizing more, fertilizing less, adding CO2, playing with their lights, etc., whichever they happen to be doing when the problem solves itself is attributed with curing their algae problem. New tanks take more work, more cleaning and more care. Do this and exercise a little patience, a lot of problems disappear on their own.
B.) Grow plants. Plants need light, CO2, and ferts. Light can be problematic, almost everyone seems to use much more light then they need and a lot less CO2 and ferts. I don't think you have too much light, so I'd start by concentrating on the second two. Could just be the pics you've posted but your plants look a little pale to me. This could be lack of CO2, lack of ferts or a combination of the two. If it were my tank I'd add either CO2 or Excel (or substitute). I'd also add macros (nitrogen, potassium and phosphate). Give the plants whatever they need to grow.
C.) Balance is a meaningless buzzword used by too many people. Don't be scared of ferts or CO2. I've never seen any evidence that overdoing them has caused any problems in any of my tanks. You CANNOT starve algae. You CAN starve plants. An aquarium is always going to have more then enough nutrients to sustain an algae outbreak. And starving (dying) plants are fuel for algae outbreaks. So don't worry about over-fertilizing. I can't say what would happen if you dumped a whole bottle of Flourish in a tank, but short of that 2 or 3 or 4 times the recommended dose won't cause any problems in an otherwise well run tank. There is no magic ratio! And as an aside Flourish Comprehensive is not comprehensive, there are not enough macros in it to sustain a planted tank. The product is essentially designed for a fish tank with a couple of plants.
D.) Use lots of plants. Tanks with a large plant biomass are a lot easier to run then tanks with less plants. Some people attribute this to competition for nutrients. Every successful EI tank proves this theory wrong. Lifeforms (algae and plants, in our case) compete to dominate systems. I haven't heard a theory that I believe, on how they compete but they do. Most of the tanks that are algae free that you see on this site and others have large amounts of healthy growing plants. Now check out the pics of tanks of people who are having problems. You will almost invariably see a lot fewer plants. I believe your tank would benefit from some more fast growers. Pack it full until the time the tank stabilizes, then you can remove, or change out plants, as you wish.
Hope this helps some. As a point of comparison, I have a 10 gallon with 2 13 watt cfl bulbs. This tank wouldn't have any greater light levels then yours since they are just stuck in an incandescent hood. I've played with the tank a lot. I've run it with DIY CO2 and ferts with no algae. I've run it with excel and ferts with no algae. I miss water changes. For some periods, I fertilize religiously (3 times a week, full EI). Some times I get lazy and only fert once a week. This tank is mature, so I have a lot more leeway with it then you have with yours. Point is, with a little work now, fert regularly, clean religiously, provide steady amounts of carbon, your tank will get to the same point.
Wishing I had a pithy quote