Nymphoides Hydrophylla (Taiwan Lotus) Yellow Leaves & melt Problem

[ayman.roshdy]

I have a low tech tank (no CO2 and medium light), I have several low tech plants in this tank (the list at the bottom of this post), the only plant that is not doing good is the 'Nymphoides Hydrophylla (Taiwan Lotus)', after a while the leaves' color changes to yellow and melt from the leave border onward, I usually cut out those leaves after a while

Don't know exactly what is happening with this specific plant, the last time I got this plant it was shaded by other bushy plants and I thought that this was the issue but now nothing is shading it plus all the other plants are doing great, any clues?

The list of plants are:

• Limnophila Sessiliflora
• Cryptocoryne Wendtii Brown
• Hygrophila Polysperma Sunset
• Hygrophila Polysperma
• Hygrophila Difformis
• Echinodorus Grisebachii (Amazon Sword)
• Bucephalandra Godzilla

Thanks

The leaf highlighted by the red circle is an example of the problem:

 

[GreggZ]

The good news is most of the plant looks healthy. If it's just one or two leaves once in awhile then just pinch those off and the plant should do fine.

Pinpointing the cause will be tricky. Lack of light is one possible cause, but the plant looks like it is not shaded. Next would be a nutrient deficiency. Mostly likely NO3 or Fe, but could also be PO4 or K.

How are you dosing the tank? The rest of the plants look like they are in good health so I would not change anything drastically just in small increments.

 

[BigWave]

I'm with Greggz, inclined to say fertz problem. NO3 problems appear as leaf melt quite often. Did you by chance place root tabs under this plant? It is quite a root feeder.

 

[JPog]

The heavy root feed thing to me is a slippery slope. If true, does it require ferts to exist in a physical state in the substrate or does it simply take from the water column through the roots, since the column ferts go everywhere anyway.

 

[BigWave]

@JPog I totally understand your thinking. The way I see it is more the citations of the elements. For example we know plants in the water column absorb the NO3- citation but if there are NH4+ citations floating around bacteria have to convert them into NO3 for the plant. Now in the root zone plants absorb the NH4+ citation directly or via a symbiotic relationship with bacteria. Now we see it all the time in terrestrial plants feeding one type of N source vs the other changes all kinds of characteristics. Id wager the same for our plants.

 

[ayman.roshdy]

I'm with Greggz, inclined to say fertz problem. NO3 problems appear as leaf melt quite often. Did you by chance place root tabs under this plant? It is quite a root feeder.

I placed some root tabs below all the plants, but can increase them for this specific plant in the coming maintenance

 

[ayman.roshdy]

Regarding the dosing regime:

• The overall water volume is 112 liters (30 gallons)
• I am dosing on a weekly basis before the 50% water change by 3 days:
  • 7.5 ml Iron
  • 7.5 ml Macros (NPK)
  • 7.5 Potassium (this is considered redundant, so was planning to reduce or stop all together)
  • 7.5 ml Micros (Fe - Zn - Mn - B - Mo)

The rest of the plants seems to like this regime but not this plant, the reason I am dosing before the water change by only 3 days is that these ferts tend to cloud the water a bit (specially the Iron) and I don't really like the look of the tank

Let me know what do you think about this regime and what to change, noting that it is a low tech tank, and I was planning to reduce the ferts after the plants are established/grown more in the tank, the overall age of the tank is 1 month

Thanks for the continuous help and support, it is a real pleasure to be part of this group/forum

 

[JPog]

@JPog I totally understand your thinking. The way I see it is more the citations of the elements. For example we know plants in the water column absorb the NO3- citation but if there are NH4+ citations floating around bacteria have to convert them into NO3 for the plant. Now in the root zone plants absorb the NH4+ citation directly or via a symbiotic relationship with bacteria. Now we see it all the time in terrestrial plants feeding one type of N source vs the other changes all kinds of characteristics. Id wager the same for our plants.

Yep, I hear what your saying. I just realized this is low tech, I also wonder if having nh4 directly in the substrate makes more of a difference in low-tech since the plant makes easier use of it.

@ayman.roshdy What kind of root tabs are you using? They certainly can't hurt as long as they don't foul the water, but you want ones with a useable N source and not something like Flourish tabs.

 

[ayman.roshdy]

Yep, I hear what your saying. I just realized this is low tech, I also wonder if having nh4 directly in the substrate makes more of a difference in low-tech since the plant makes easier use of it.

@ayman.roshdy What kind of root tabs are you using? They certainly can't hurt as long as they don't foul the water, but you want ones with a useable N source and not something like Flourish tabs.

I am using Tetra InitialSticks; I checked their website and it mentions "Contains valuable natural and mineral ingredients such as humus, clay minerals and iron, which support root formation", so I don't think they contain N, but on the other hand I am dosing liquid Macros which contains N, will look around for another root tabs that contain N, but I think it will melt completely before I can find some, today 2 leaves melt and died, I think the rate is increasing now !