Argentine Sword- Emersed Or No?

About two months ago I bought an Argentine Sword at my LFS. It was totally submerged and it was dying- the leaves were rotting away.

I wanted this plant because of someone I know who has a gorgeous one growing emersed in a low-tech tank- the roots are in the tank, and there are lovely long stems growing up out of the tank, with the leaves completely out of the water. It looks amazing.

I asked him about the plant I bought and his advice was that it was rotting because the leaves should be grown emersed, and that I should cut it back to stems, plant it in those glass pots that stick to the side of the aquarium, and let it grow while slowly moving the pots towards the substrate so that the leaves would always remain emersed.

So far so good, I cut the plant back so there were no leaves and potted it. The leaves started to grow back quite well at first, and I was looking forward to moving it down, but the stems never started to grow long, and now they are withering away for no apparent reason. It almost looks like they're burning, but it's not that close to my light fixture. I can't work out what's going on here. See photo.

The person who first advised me is unavailable now so I'm turning to you guys.

What should I do now? How do I get this plant to grow emersed? Co2 is not currently an option for that particular tank but my acquaintance doesn't use it either.

 

I'm not an expert or experienced with this plant, but it rather looks like it's decaying from maybe lack of nutrients. It it on substrate or in it? What is that substrate? Do you fertilize it? Why is the water so dark?

 

I'm not an expert or experienced with this plant, but it rather looks like it's decaying from maybe lack of nutrients. It it on substrate or in it? What is that substrate? Do you fertilize it? Why is the water so dark?

The water is not dark, it's a trick of the light caused by the substrate- the pots have organic potting soil at the bottom which is capped with black sand (this is why you think the water looks dark).

The pots are mounted on the wall of very clean Walstad tank (if you look to the left of the pots, you can see the water is very clear, you can see clear water down to the rocks which are grey). The tank is also organic potting soil capped with black sand, it was only planted about ten weeks ago so there should be no reason to use ferts yet (but I can if someone here disagrees with that assessment- I'm just afraid of overdoing the nutrients when using potting soil).

Edit: Doh, I just realised that I should move the pots down so that the water in them is circulating instead of being stagnant...but would the fact that I overlooked this make this plant look that unhealthy?

 

Not keeping the leaves moist? They look dried up.

 

Edit: Doh, I just realised that I should move the pots down so that the water in them is circulating instead of being stagnant...but would the fact that I overlooked this make this plant look that unhealthy?

Sometimes, yeah, I've had plants that started rotting or melting in stagnate water. I think maybe there's too much organic buildup or something? I dunno. Roots can rot. Maybe you can poke around or pull them out and make sure the roots are still healthy? If the roots aren't able to pull up nutrition to the plant, the leaves will be affected.
(not a plant expert, just a plant lover--don't quote me.)

The water is not dark, it's a trick of the light caused by the substrate

I thought that might be the case but wasn't sure.

The tank is also organic potting soil capped with black sand, it was only planted about ten weeks ago so there should be no reason to use ferts yet

I figured as much but didn't want to assume. I'd expect the soil would still have nutrients.
Again, I'd check the roots to make sure they're doing okay. Sometimes roots don't like being in constantly wet soil and will start to decay, I think maybe because of the dense organic matter or something? Again, I don't know for sure, just guessing from my past experiences and observations.

 

Thanks for the advice. I kind of feel like a dolt right now. I moved the pots down so they've got circulating water...I put them low enough so the dead leaves are partly underwater and my amanos are cleaning up the dead parts, once the amanos are done I'll see what state the roots are in. With some luck maybe they will regenerate again.

I know those glass pots aren't big enough to house a sword plant permanently (not that this was mentioned, I'm just musing), my hope was that I could eventually plant them at the bottom of the tank.

Was my acquaintance correct in saying that this species of sword should not be completely submerged?

I really hope I can manage to save these!