Low tech 55gal super-slow sword growth
I've had swords in my 55gal tank for a long time. When I first put them in, I had a single T8 bulb over the tank, and it was way under-lit.
A couple of months ago, I upgraded the tank up to low lighting, and added root tabs under every plant. I also added a couple chain micro swords and a couple nanas. At this point I had the following in the tank: swords with small leaves, java fern, java moss, anubus nana, micro chain sword.
Since then, the nana has perked up, and maybe put out one new leaf each. The chain swords both melted (they were growing emersed) and have since recovered. One has sent out a single runner. The java moss has grown a bunch. The java fern has grown some, nothing impressive.
But, the amazon swords have done basically nothing. One of the big things I was hoping that the lighting upgrade would do is produce bigger leaves in the swords, but alas. I haven't noticed any new leaves, and the existing leaves haven't grown noticeably. They are all about 4" long... as opposed to the 12-18" leaves that I was hoping for.
Water parameters: I have not dosed the water column at all, but have osmocote plus root tabs under each plant. Drop checker is consistently very blue-ish, so I know the CO2 is limited. GH/KH are both between 5 and 10 deg out of the tap. No major algae issues, some grows but the shrimp/snails keep it clean.
So, what do you think? Do I need to move up to supplying CO2 and dry ferts in the water column? I'm hoping to keep the tank low tech/maintenance, but want to get some growth out of my swords. I've considered replacing the plants to see if they just got used to producing small leaves because of being exposed to insufficient light for so long. I'm hoping to get runners out of my chain swords a bit more often.