Floating plants: Do I need to remove the submerged ones?

[Ben Rhau]

Hello, plant people. I now have a number of different floating plants across my tanks, and have some basic questions about maintenance. My main question concerns the (few) plants that linger just below the surface and do not stay dry. Is it crucial to remove these so that they do not increase BOD, or might they eventually recover?

Salvinia minima:
1. While most of my plants are clearly dry and hydrophobic at the top, I do notice that some of the plants stay wet. These are often crowded with other plants or are near the air pump lift tube, where they have trouble avoiding splashes. There is very little flow, so I've surrounded the outtake with a feeding ring. However, the plants near the ring still get wet. Should I discard these "wet" plants? I've tried rescuing them by moving them to a different areas of the tank, but so far I have not seen them recover.
2. There is obviously a lot of growth, and some of the original leaves are becoming dark and senescent. However, they are attached to new growth. Should I try to separate these leaves and discard, or just wait until this happens on its own?

Red root floaters:
3. I know these aren't easy to keep for low light tanks, but I'm trying it anyway. Again, some of these plants have a significant portion that remains submerged. I do see new growth emanating at the surface, but I cannot separate them from the submerged parts because I'd lose the roots. Should I remove these, or baby them along and hope for the best?

The "easy" plants so far have been: Amazon frogbit, Pistia stratiotes, Salvinia cucullata. The Salvinia minima are easy, but as the new leaves are significantly smaller than what I originally added, I'm guessing my LED isn't outputting enough light for them to thrive.

Thanks,
Ben

 

[Ben Rhau]

Pinging @dw1305 : As a general rule, once a floating plant like Salvinia minima loses its surface tension to stay dry at the top, is it possible for it to recover, or is it doomed? If doomed, I'd be more aggressive in taking them out.

For example, in my QT tank, most of my S. minima are not dry at the top, I'll swap them out with healthier ones just to be safe, but am wondering if the plants are a net positive or net negative on the tank if they are slightly submerged.

Thanks

 

[dw1305]

Hi all,

Pinging @dw1305 : As a general rule, once a floating plant like Salvinia minima loses its surface tension to stay dry at the top, is it possible for it to recover, or is it doomed? If doomed, I'd be more aggressive in taking them out.

Doomed I think. I'd probably replace them with one of the other floating plants. I tend to remove the leaf pairs from Salvinia spp. when they go brown or are submerged.

What do the plants look like? It maybe iron deficiency if the old leaves are very brown and the new leaves small and pale?

Red Root Floater.....Again, some of these plants have a significant portion that remains submerged. I do see new growth emanating at the surface, but I cannot separate them from the submerged parts because I'd lose the roots. Should I remove these, or baby them along and hope for the best?

It didn't enjoy life with me, it slowly dwindled and then lost the surface battle to the other plants. I had the same experience with Hygroryza aristata, so I assume they both need more nutrients than I have to offer.

cheers Darrel

 

[Ben Rhau]

Thanks, Darrel. That's helpful.

What do the plants look like? It maybe iron deficiency if the old leaves are very brown and the new leaves small and pale?

In my main tank where they are growing, yes they have that appearance. They multiply, but the leaves are very small. They get Flourish (trace elements with 0.32% iron) and potassium 3x a week, nitrogen 2x a week. In my QT tank where most of them were dying/wet, I think it's because I dimmed the LEDs drastically to minimize stress on the fish. I didn't think about the possibility that it would kill the Salvinia, so tonight I replaced them with "dry" Salvinia and turned up the light. Hopefully they'll grow better this time around.

Would you recommend supplementing with iron, or just giving them Flourish more often?

It didn't enjoy life with me, it slowly dwindled and then lost the surface battle to the other plants. I had the same experience with Hygroryza aristata, so I assume they both need more nutrients than I have to offer.

Both my Salvinia and Phyllanthus grew just fine in the bucket for a month. It wasn't until I added them to the tanks that they started struggling. There should have been no difference in nutrients since they were growing in tank water, supplemented on the same schedule. So to me that says they need more light than my LEDs can throw. I can also try increasing the photoperiod. Right now the get 3.5 hours in the morning and 5 hours at night.

-Ben

 

[dw1305]

Hi all,

So to me that says they need more light than my LEDs can throw.

Sounds likely, I always have the lights on full, I just have more plants in the surface layer when I have a brighter light.

Would you recommend supplementing with iron

I might try a different chelator. "Flourish" uses ferric gluconate, which is cheap but not very effective, and to add enough via "Flourish" you could run into micro-nutrient toxicity. Whatever you add you want about 0.5ppm Fe and it will take a while for new, non-iron deficient leaves to grow.

If you have soft water then FeEDTA is fine, I use it. If your water is harder then you need a better chelator, one that is more effective at higher pH levels. Apologies for the cross-post but have a look at UKAPS Threads <"Iron deficiency">, <"Frogbit taken a turn"> & <"Olympus is calling"> it sketches in some of the detail.

cheers Darrel

 

[Ben Rhau]

OK I will try FeDTPA, since my pH tends to fluctuate between about 6.5 and 6.8. With EDTA, I'm seeing that only 50% of the iron will be available in solution. But wow, that's a LOT better than gluconate. When you say 0.5ppm Fe, do you assume it is all soluble? Or should I dose half that for FeDTPA?

Thanks,
Ben

 

[dw1305]

Hi all,

OK I will try FeDTPA, since my pH tends to fluctuate between about 6.5 and 6.8. With EDTA, I'm seeing that only 50% of the iron will be available in solution.

FeEDTA would do. With most of the micro-nutrients the difference is between "none" and "some".

When you say 0.5ppm Fe, do you assume it is all soluble? Or should I dose half that for FeDTPA?

Yes 0.5ppm whatever iron chelate you use.

Have a look at <"UKAPS: Calculating with DTPA">.

cheers Darrel

 

[Ben Rhau]

Update: For the salvinia minima, more light was the answer, so I’m slowly switching over my tanks to higher output lights. Everyone is getting 0.5ppm iron now, as well, which my water sprite and crypt are happy about.

Red root floaters: Struggled in the beginning, but I’m successfully recovering them by placing individual plants in a feeding ring until they grow enough dry leaves to remain buoyant. I’ve also placed a feeding ring above my sponge filter lift tube to reduce surface agitation and splashing.

Question: In one tank, I’m seeing holes in some of the frogbit and red root floaters. Picture below. Does this look like physical damage or nutrient deficiency? It’s a newish tank, so it doesn’t have many snails. It has amano shrimp, though. It gets 6ppm of potassium a week.

Thanks,
Ben