Colin answered the Kelvin question. Scientifically-controlled studies have shown that aquarium plants do best with light in the 5000K to 7000K range. The lower the K number, the more red and less blue in the colour spectrum, so "warm" white; the higher the K number, the less red and more blue, so "cool" white. Marine tanks require high blue especially for corals, but freshwater plants do best closer to mid-day sun, which is as Colin noted, around 6000K. So your spectrum is fine.
As for the intensity, I've no direct experience with LED. Other members may be able to offer guidance. I'm still using T8 fluorescent tubes or on my smallest tanks CFL bulbs. Watts is no longer any guide to intensity unless one is comparing absolutely identical tubes/bulbs; watts is simply the energy required to light the tube/bulb/diode. I would suggest you stay with what you have and see what develops; here, I'll digress.
Light intensity (assuming the spectrum is acceptable) drives photosynthesis which is how plants grow. Some plants need more light than others, which is why they have varying growth rates and nutritional needs. Back to that balance again. As soon as any one factor is missing or insufficient, photosynthesis slows and may even cease altogether. So in your tank, the Wisteria is fast growing which means it needs brighter light than the moss or Anubias, which are both slower growing. But if the necessary nutrients are not available, the plant cannot use the light. Algae is less demanding, so it is always able to take advantage of any imbalance. Which is why finding or establishing and then maintaining the balance for each individual aquarium is important.
Duration is important, but it cannot "make up" too little intensity. The intensity is essential to drive photosynthesis, and plants will photosynthesize fully out if light and nutrients are available. But we can control this somewhat by lessening duration, to ensure we do not unbalance things if nutrients may be limited--as here they are, because primarily there is no plentiful source of ammonia/ammonium as there are with fish. [An example of this is my 20g quarantine tank for newly acquired fish, which is planted and runs permanently; when there are no fish, for months often, the plants manage to hang on, but barely; as soon as I add some new fish for a few weeks, the plants show positive response. This is the ammonia, and likely also CO2, created by the fish being present and being fed. Organics also increase too, more nutrients.] I have found that 8 hours is maximum for all of my tanks except one, which has 7 hours of tank lighting; any more and nuisance algae appears. But this balance is determined by the plant species, plant number, and fish load, for each tank. I have all low and moderate light requiring plants; higher light plants simply will not last. I also have floating plants in all my tanks, primarily for the benefit of the fish, and this obviously lessens the light intensity some. Wisteria for example will not grow in my tanks, due to light (too weak). If you can reduce the duration to 8 hours, it might improve things.
The other factor in balance is nutrition, and to answer your question about fertilizers...you want a comprehensive supplement that has basically everything plants require. Hydrogen, oxygen and carbon are never included, as these occur from other sources. I use Flourish Comprehensive Supplement for the Planted Aquarium and have for several years; another basically identical is Brightwell Aquatics' FlorinMulti. Not only do these have all necessary nutrients, the nutrients are in proportion to each other according to the needs of aquatic plants. Any one of these nutrients in excess can cause trouble, not only for plants, but algae can make use of such imbalances. Some nutrients in excess cause plants to shut down assimilation of certain other nutrients, so the balance among nutrients is important. In a high-tech method planted tank with mega light, diffused CO2, and daily nutrient dosing, you can over dose to some degree and then restore the balance with massive water changes. But in low-tech or more natural systems, any imbalance can wreak havoc very quickly.
I have seen Flourish Advance but not used it. First, it is not a nutrient supplement as is Flourish Comprehensive, and second, my tanks with plants have been running for many years and I am somewhat adverse to adding more chemicals when not really necessary. Every substance added to the water does get inside the fish, and "safe" is rather a subjective term manufacturers toss around. There is no doubt whatsoever than fish are affected by all chemicals and additives, so keeping them minimal is always better. You don't have fish to worry about here, and in a new set-up Flourish Advance might help. I wouldn't continue it though, it is expensive and as I say provides no nutrients itself.
