your tank looks fine ; it's normal to have some algae here and there ; but I do not agree with some of the comments above : CO2 is the most important fertilizer and if absent will limit plant growth regardless of how much of the other elements are supplied : light, N, P, microelements, etc which will end up "fertilizing" the algae growth; what I mean is that you should try to "bring balance to the Force " , to supply the elements - light, fertilizers - in a proportionate manner given the absence of CO2; I would double the recommended dose of Excel given the light and fertilizers' levels in your tank; and increasing the water surface mouvement will lower the dissolved CO2, the same as an air stone
and by the way , do you have a nutrient rich substrate under that sand ? if not, you should add some tablets or some other root fertilizer for that hungry bottom feeders like Echinodorus and red plants; I would add more crypts as they are resilient and undemanding, like C.parva and C. albida brown, to add more color and detail to the bottom with their small leaves