I use Seachem's Flourish Tabs for the larger swords, and when I had them the Red Tiger Lotus and Aponogeton. But I also use Flourish Comrehensive Supplement in all my tanks because the surface is covered in floaters (this also lessens light getting to the substrate, but the chain swords thrive). So the chain swords are growing well with moderate to low light and Flourish Comprehensive once a week.
I only use the Flourish Tabs brand because they release nutrients as the plants use them, and not into the water column. I don't know how they achieve this, but I do believe it is accurate because when I changed from just Flourish Comp to the Comp (less) plus the Tabs, algae decreased.
These are a couple of my tanks with the chain swords.
