Hi Denis,
Light and CO2 uptake demand are tightly linked by an enzyme produced within the plant. As the light energy increaes, so must the enzyme whose job it is to collect the CO2 and strip the carbon. If there is more light energy than the available carbon the plant disintegrates as it attempts to canabalize itself to recycle as much of the available compounds.
"X" amount of light requires at least "X" amount of CO2, "Y" amount of light requires at least "Y" amount of CO2. You've exceed the threshold of light for the level of CO2 in the tank so you must either lower the light or increase the CO2. My personal choice would be to move the fish if you have an alternative home for them, clean as much of the algae by hand, do 2 or 3 water changes per week (dosing after each change) and pummel the tank with CO2 and EI level of nutrients. After 6-8 weeks you will have generated enough plant mass and bacteria mass, the dust will have settled and the plants will be well established and growing. You can then reassess to lower the light and/or to fine tune the dosing scheme. The thing is that these factors are all linked. Light creates demand for CO2 which in turn creates demand for nutrients.
The current situation is that as the plants disintegrate they eject whatever nutrients they have accumulated (as well as ammonia) into the water column. The ammonia in the precesnce of light triggers the algal bloom. When the bllom occurs the algae then feeds on the nutrients that are present. There is an optical illusion in which many people think that the nutrients caused the algae but as you yourself can attest, you started seeing algae and then you got the fish, remember? That means the tank was on the decline way before you added more nutrients.
It is a steep learning curve, no doubt but I'm convinced that EI plus massive CO2 is the best way to go. It's always going to be difficult with such low plant mass. Healthy plants remove ammonia from the water and deterrs the algae. Plants in poor condition due to starvation release ammonia into the water.
In the CO2 article I mentioned that ON/OFF is optional to 24Hrs which is less compllicated since there is no need for a solenoid. I actually prefer ON/OFF because it allows you to inject higher daytime CO2 levels while giving the fish a rest at night when the plants cannot use CO2 but do consume O2. If you have a solenoid then ON/OFF is the way to go.
Keep reading mate, the curve flattens a bit after we unlearn the myths and realize the truth.
Cheers,