You are always going to have various opinions on any forum. And remember that all tanks are different and what works in one may not work in another.
I've had two tanks set up exactly the same in the same room, using the same lights, ferts, and liquid carbon and each tank had different growth rates and even different parameters when tested. I have 2 55g planted tanks and both have a 2 bulb AquaticLife T5HO fixtures. Due to the depth of the tank I have at the very best medium light.
Now many plants, swords included in this group will grow fine in less light but they will not grow nearly as fast. Also when using a floating plant that covers the entire surface you cut the amount of light reaching the plants below drastically. So all this being said is you have to make a decision on how you want to try to run your tank. Maybe T8's will do fine and maybe not, they are a good cheap option.
BUT your biggest issue is ferts. The pic's of the plants you posted show several nutrient deficiencies so it is obvious your not using enough ferts in the tank but the fert you using may not have everything plants need. Plants need both macro nutrients (nitrates, phosphates, potassium, calcium, magnesium) and a bunch of different micro nutrients.
Most all liquid ferts contain mostly micro nutrients and very little if any macro nutrients. I often tell people who want to use liquid ferts to use a combination of both Seachem Flourish Comprehensive along with API Leaf Zone which provides only potassium and iron. Since most tanks produce both nitrates and phosphates via fish waste and fish food, the above combination provides a good mix of the other nutrients needed. Also when using liquid carbon which aids in photosynthesis and plant growth your plants grow faster which also means they need more nutrients.
