Black leaf edges - cause?

[TrevC]

Hi - I am trying to understand why some of my plants are suffering from blackened tips and edges. I recently increased my light intensity and a little bit of green spot algae has appeared - particularly on some anubias, lymnophila aromatica and (newly introduced) Staurogyne repens. This green spot algae in itself is not the main concern as its all part of find the right balance I guess. What is confusing (having trawled any number of discussions on this subject and looking at the algae guide referenced in this forum), as to why the black edges have appeared. Is doesn't appear to be BBA so there are three factors as I see it

1. the black edges are a consequence of the green spot algae on plant health
2. it is algae itself (very unlikely?)
3. it is an unconnected issue such as a nutrient deficiency

As a relative newbee I wanted to seek advice as the various forums have left me confused. If anyone can shed light on this I'd appreciate it so I can plot the right course.

My tank details are:
1. Size of tank. 90cm, 45cm, 60cm
2. Age of the system approximately. 6 months
3. Tap water parameters. Not known
4. Filtration. Betta 1040 with UV; includes charcoal, purigen, ceramic rings and Matrix
5. Lighting and duration. Fluval Plant 3.0 46W (3300 lum max? 6500k ) 8hrs with 30min ramp up and down; currently at 75% of the default 'planted tank' lighting profile
6. Substrate. Fluval stratum in filter bags capped with riverbed sand.
7. Co2 dosing or Non-dosing. Yes. I get stable CO2 during the photoperiod and 1.0 pH drop from the fully degassed reference
8. Fertilizers used + Ratios. TNC complete default dosing (changed a few weeks ago from default dose to 2x default dose)
9. Water change regime and composition. 30% per week
10. Plant list. Bolbitis heudelotti, Bucephalandra Theia, Anubias barteri Petite, Anubias Nana, Microsorum pteropus Trident, hygrophila Siamensis 53b, limnophila aromatica, limnophila sessiflora, alternanthera Reineckii Pink, varous mosses, assorted crypts (Undulatus Kasselman, petchii), Monte Carlo, Staurogyne repens plus Salvinia floating plants;
11. Inhabitants. 15 shrimp (amano and cherry), 7 neon tetras, 8 copper harlequins, 3 red platys, 2 neon blue dwarf gouramis, 5 red phantums, 4 Ottos (all very fat and happy!)

 

[Le duke]

Iron deficiency?

Unless you can turn off your UV and have it running during hours of darkness, and fertilize during daylight, it’s likely nuking your iron.


Sent from my iPhone using Tapatalk

 

[Hufsa]

It is possibly the effect of microcystins produced by the algae.

"For plants, MCs adversely affect physiological processes, including tissue development, enzyme activation, gene expression, photosynthesis, and other processes necessary for a plant to grow. Additionally, MCs can inhibit or promote mitosis at different doses." - <source here>.​

​

It is fair to say that there is an evolving understanding over the role of these microcystins. There is a <recent publication> that is worth a quick read because it sheds a great deal of light on algal toxicity and these types of compounds. The authors seem to have acknowledged the growing body of evidence into the allelopathic impacts of algae on plants, but you will also come across <older studies> that did not quite back this position and referred to it as "hypothetical". Whereas I think most scientists, those with enough insight, would back this position today and accept that it can give algae the potential to have an impact on aquatic plants. Allelopathy is everywhere, <even in my back garden>... But research is still found wanting.

Im sorry to be so blunt but is this the most relevant information for the original poster?
I only say something because we have recently had forum announcements where the moderators ask that members try their best to explain things to users asking for help in as easy to understand language as possible.
And more advanced topics are best discussed in their own threads.
The OP (Original Poster) has already indicated that they have searched for advice already on a variety of forums and has mostly gotten more confused (which I can definitely understand).

I think we can figure this out together with the OP, but I think they might appreciate something that is easy to understand and more specific to their situation at hand 🙂

it is algae itself (very unlikely?)

In my experience a thin black to dark brown line along edges of leaves have been a diatom type of algae. In my tank, these edge lines have gone away on their own when the tank is mature enough.
You say the tank is about 6 months old (kudos for providing the information up front btw ), so its not unheard of to have a bit of diatom algae going on still.
Diatoms can even come back in a mature tank if the tank has been destabilized for any reason.

If the line on the edges of leaves never develop into anything thicker or that protrudes from the leaf, its likely to be diatoms.

Sometimes we see forum users who have something a bit thicker and more "3D" though, then I would start thinking about BBA, staghorn and perhaps cyanobacteria.
Both the red algae types (typically blackish-grey in color in the aquarium) and cyanobacteria can look almost black in some circumstances.
There are many different species of algae in those categories, so they dont always look the exact same way in every aquarium setup 🙂

4. Filtration. Betta 1040 with UV; includes charcoal, purigen, ceramic rings and Matrix

How long has the Charcoal been in there? I dont necessarily think its related to the algae, but if using charcoal it needs to be replaced periodically, otherwise the things it has absorbed will start leaking out of the charcoal again.
I would just remove it entirely and not replace it, personally.

5. Lighting and duration. Fluval Plant 3.0 46W (3300 lum max? 6500k ) 8hrs with 30min ramp up and down; currently at 75% of the default 'planted tank' lighting profile

The increase in light is probably not a coincidence. The Fluval 3.0 is not the strongest light on the market (this is not necessarily a bad thing btw), so overall your light level is not gonna be as crazy as someone who turns their Vivid up to 100% or something like that, which usually leads to trouble. Could you try cutting down the light period for an hour or two, and see if the algae backs off a little bit? Lowering the lighting period or the lighting intensity is usually a "first aid" when dealing with algae issues.
Its not that the light decrease actually fights algae, but it slows the system down a little bit while we have time to work on the underlying cause.
It gives a little bit of breathing room while we can make sure your CO2 injection is fully stable, and your plants have all they need to grow completely healthy.

7. Co2 dosing or Non-dosing. Yes. I get stable CO2 during the photoperiod and 1.0 pH drop from the fully degassed reference

Can you give us more details on how you inject CO2 and how you measure the PH drop Have you done a full PH profile?

8. Fertilizers used + Ratios. TNC complete default dosing (changed a few weeks ago from default dose to 2x default dose)

Was this changed around the same time as the light increase and algae appeared?

9. Water change regime and composition. 30% per week

You could bump this up to 50% per week for a while if possible, it just makes it easier to know whats going on in the tank.

10. Plant list. Bolbitis heudelotti, Bucephalandra Theia, Anubias barteri Petite, Anubias Nana, Microsorum pteropus Trident, hygrophila Siamensis 53b, limnophila aromatica, limnophila sessiflora, alternanthera Reineckii Pink, varous mosses, assorted crypts (Undulatus Kasselman, petchii), Monte Carlo, Staurogyne repens plus Salvinia floating plants;

Can we get a full tank picture? 😃 Im interested in how many fast growing plants you have vs slower growing. Is there any way you could get your hands on some Amazon Frogbit? Just a small handful would do.

With a few more details I think we can help you figure this out
I think it looks like there are a few areas where your plants could grow better, and addressing that should help some with the algae.

 

[Hufsa]

A few more things, sorry 😅

8. Fertilizers used + Ratios. TNC complete default dosing (changed a few weeks ago from default dose to 2x default dose)

How do you dose ferts? Once a week, multiple times? Include how you have done it previously, and how you do it now, if those are different.

9. Water change regime and composition. 30% per week

Do you add any Magnesium to your water change water?

 

[TrevC]

Hi Hufsa

Thanks for your help. In response to your comments:

1. Diatoms? I do have some classic brown diatoms in the tank (see substrate and the Lymnophila sessiflora on left in full tank picture). The 'black line' I see on older leaves has no 3D element so could be diatoms as well I suppose given what you say but it does not rub off. I attach a close-up pic of my Anubias petite leaf which shows things quite clearly.
2. Filtration - i change the charcoal every two months.
3. Lighting. With similar thinking in mind, from yesterday I already removed the ramp up/down and reduced lighting period by an hour to 7 hrs in total.
4. CO2 profile. I use a Strideways system with inline diffuser. Several weeks ago I spent some time looking at CO2 and ph drop (using liquid tests and drop checker) as per post ph profile for 230l tank - confusing results The current profile is summarised in the attached graphic with the fully degassed reference at about 8.0, pre-injection level of 7.5, stability during light period around 6.8 and aeration after lights out bringing the pH back up quickly to 7.5
5. TNC dosing - the algae appeared prior to the dose being doubled. Again was exploring the balance...
6. Water change - the one last week was about 40% but will try 50%.
7. Full tank picture and fast growing plants - see attached. For me, Lymnophila sessiflora needs continual weekly pruning (though as i said above, the lower portions seem to have a tinge of brown diatoms). The Hygrophila Siamensis 53b and Alternathera Reineckii Pink grow very well also. The Monte Carlo and Staurogyne repens at the front are relatively new (1 month). I also attach a top view and you can see the black lines clearer on the older leaves of the Limnophila aromatica on the left and Hygrophila Siamensis 53b on the right
8. Fert dosing - has always been daily in the morning.
9. Magnesium - not added to WC water - just water straight from the tap with Microbe-Lift Extreme water conditioner.

Hope this informs adequately. Open to all advice

 

[Oldguy]

Magnesium - not added to WC water

Just an aside, magnesium is often overlooked - typically very low in UK tap water, can be locally high.
May be the black is not a growth on the plant but a mode of plant growth, caused by a yet unknown factor, only time will tell.
I have had the occasional black tip on Java Fern which I put down to lighting being too bright for the plants slow growth rate. (The plant had grown from shade upward into bright light at the top of the tank.)

 

[bazz]

Hi,
Looking at your Full Tank Shot (which is very nice) with your plant mass it could be that you require a more flow especially lower down. Your 60cm high tank is 230l and your filter only outputs 1040l/hour whereas high tech tanks usually require 10x (manufacturers claim) flow. From the photos I can't make out your filter return method into the tank but it's quite possible a strategically placed powerhead lower down in the tank which complements your existing flow will help. I have a 230l tank also and use a AI Nero 3 for this same purpose running at 15% while CO2 is on and 1% when it is off and it works wonders.
Changing more than 50% of your water volume each week will also benefit your tank ensuring there is nothing building up to toxic levels and ridding the tank of organic waste.
I'm unsure how to calculate your Magnesium content from your dosage of the 0.8% TNC to dGH, but I'm sure adding one or two teaspoons straight after water changes should bring it more inline with 3-1 Ca-Mg ratio which is widely accepted.
All of the above are just my personal beliefs and we all know there is more than one way to skin a cat.
Cheers!

 

[Hufsa]

Diatoms? I do have some classic brown diatoms in the tank (see substrate and the Lymnophila sessiflora on left in full tank picture). The 'black line' I see on older leaves has no 3D element so could be diatoms as well I suppose given what you say but it does not rub off. I attach a close-up pic of my Anubias petite leaf which shows things quite clearly.

Yes I strongly believe its diatoms. For whatever reason the black lined leaves that appear sometimes are not as often mentioned when diatoms are being discussed, usually its the brown film or the brown stringy type that is discussed most.
That you have diatoms in other areas of the tank supports my suspicion. It didnt rub off when I had it in my tank either.
Im not sure what it is they like about the edge of the leaf, if I had to guess it might be a particularly nice spot for them to grow.
BBA often grows on the edges of leaves too, so the diatoms dont seem to be alone in thinking its a nice place to live.


This is a mild coating of diatoms.


Medium coating (see the edge starting to appear dark)


Strong coating of diatoms, making the tip of the leaf and the edges dark brown.

A really good thing about diatoms is that its one of the easiest algae types to get rid of. The main ingredient is time, and one of the other ingredients is stability which usually comes with time

1. Filtration - i change the charcoal every two months.

Any particular reason why you use the charcoal?
That and the UV makes me pause a little bit, mostly because it might be hard to quantify the effect they could have on the fertilizer that you are dosing.
UV breaks the chelation of the trace nutrients in the fertilizer, so it could potentially lead to less of the fertilizer being available to the plants. But there is no consensus on this matter so far.

1. Lighting. With similar thinking in mind, from yesterday I already removed the ramp up/down and reduced lighting period by an hour to 7 hrs in total.

I think thats a good choice for now, once we have a few of the issues ironed out then you can likely slowly ramp it up to wherever it is you want to have it, however the key is after issues have been resolved and slowly 😊

1. CO2 profile. ...(using liquid tests and drop checker)

Hm ok, liquid tests arent really very good for doing a ph profile, you kinda need something a bit more accurate. But right now I dont believe that CO2 is likely to be your biggest issue, based on what your plants are telling us 🙂
So its possible that its fine as it is.

1. TNC dosing - the algae appeared prior to the dose being doubled. Again was exploring the balance...

Alright. I took a look at your dosing level in Rotala calculator. I think you should continue with the double dosing at least, that should give you;
NO3 13~
PO4 1.2~
K 10
Mg 1.6
Fe 0.16
Mn 0.036
Cu 0.004
B 0.02
Zn 0.02
Mo 0.002

1. Water change - the one last week was about 40% but will try 50%.

If you can, try dosing some extra fertilizer right after a water change. It might help the plants.

1. Full tank picture and fast growing plants - see attached. For me, Lymnophila sessiflora needs continual weekly pruning (though as i said above, the lower portions seem to have a tinge of brown diatoms). The Hygrophila Siamensis 53b and Alternathera Reineckii Pink grow very well also. The Monte Carlo and Staurogyne repens at the front are relatively new (1 month). I also attach a top view and you can see the black lines clearer on the older leaves of the Limnophila aromatica on the left and Hygrophila Siamensis 53b on the right

1. Fert dosing - has always been daily in the morning.

Thats good, daily dosing gives the most even supply of the immobile nutrients like Iron etc.

1. Magnesium - not added to WC water - just water straight from the tap with Microbe-Lift Extreme water conditioner.

Aside from the diatoms (which will more or less pass when the time is right), I see a few clear nutrient issues with your plants.
Two types of chlorosis (pale leaves).
I think in order to get your plants growing even better, it would be a good idea to see if you could improve that a little bit.

Like this picture you shared of the anubias, the new growth is quite pale.
Often this is caused by not having enough Iron, but it could also be Manganese in a few cases.
Those two mainly cause issues with new growth you see.

Then there is the "wavy chlorosis". This is a kind of chlorosis where the leaf will appear a bit patterned.
Its caused by a different nutrient than Iron. Iron usually makes the majority of the leaf pale, with some green left on the biggest veins of the leaf.
Other nutrients like Manganese and Magnesium tend to leave more of the veins green, and this makes the paleness less even.
The green of the bigger and smaller veins give the leaf a sort of wavy or net pattern depending on the plant species.

If you look at the stemplant in the background here you can see the "wavy" type of chlorosis.


I have marked some plants from the FTS (thanks for that ) that also show the symptoms of either pale new growth or wavy pale leaves.
Overall the plants are much paler than they should be (although the tank looks very nice)


Since you are not adding Magnesium at water changes, I suggest you start doing that and see if the wavy pattern leaves look better. Epsom salt (Magnesium sulfate) is cheap and easy to use.
Magnesium is a mobile nutrient, so the plant can shuffle it around as needed. If the amount of Magnesium is too low, the symptoms will start on the older leaves, as the plant takes the limited supply and puts it towards the newest leaves.
Manganese however also gives a wavy/net kind of chlorosis. This one is supposed to show up in new leaves first (immobile), but it can be visible on old leaves, if those old leaves were also growing with limited supply.
If you add Magnesium going forward to your WC water, those old leaves should look better within a day or so.
If they look the same then it could be that the Manganese is also too low. Then your plants might benefit from a more focused micro dosing, we can come back to it if needed.

Use the double dosing for a while together with the Magnesium and see how that works for a few weeks.
If you could provide us with updated pictures after it has been running for a while, that would be great 😊

 

[dw1305]

Hi all,

Yes I strongly believe its diatoms.

I think it is "algal" as well.

I agree with the others add a complete nutrient mix, and hopefully plant growth will resume. The problem with nutrient deficiencies is because of the <"assembly line aspect of plant growth">.

If <"Liebig's limiting nutrient"> is totally deficient, even if it is a nutrient required in trace amounts, you don't get any growth.

cheers Darrel

 

[Hufsa]

I forgot to mention my overlying view of the "plot" 😅
Your recent increase in light means the plants are driven to grow faster. If the tank was cruising along "ok" with minor issues with the old intensity of light, increasing the light will mean that a minor issue can develop into a medium size issue, as the plants are trying to grow more but they're missing one or more "parts" that they need.
Algae are quite quick to take advantage of any slack in a system, so if the plants arent doing optimally and there has developed some room for the algae to thrive, they are usually quite fast at grabbing that opportunity.

Thats why I think this can be sorted with a few little tweaks to help the plants, because the tank looks lovely and you obviously have quite good plant growth for the most part 😊😊

 

[TrevC]

Thanks for everyone's input - this is much appreciated and gets me some tangible actions. My takeaways are that:

1. the black leaf edges are diatoms - no radical action needed other than maintaining nutrient double dosing and stability. Sounds like I should also switch off the UV light. Ironically, I replaced the bulb a week ago thinking this might help control the diatoms - it is like wrestling an octopus!! I'll also think about the charcoal but keep for now as don't want to change too many things at once.
2. For the wavy leaf issue I should dose with Epsom salts - how do I find out how much to dose?

(@bazz asked about filter return method - this is a spray bar running most of the length at the back. )

 

[Hufsa]

For the wavy leaf issue I should dose with Epsom salts - how do I find out how much to dose?

You could use Rotala butterfly to calculate the amount of salt needed.
Your tank measurements gave me 243 liters, you could round up to 250 or anything it doesn't really matter.
Id suggest adding 10 ppm Mg, or perhaps 5 ppm Mg if this is a softwater tank that you want to minimize GH in (no water data was provided and im not familiar with Cambridge water).
Generally Mg is one of the most harmless nutrients so there is no harm in overdoing a bit.
For 10 ppm thats about 25 grams for a volume of 243 liter.
I suggest dosing the full volume today, and then on your next water change you only dose the amount required for the volume of water that you are changing.
So if you're doing a 50% water change you should dose 12.5 gram (50% of 25g).
Then stick to dosing only for water replaced.
This should keep the Magnesium nice and stable.

 

[TrevC]

Hi,
Looking at your Full Tank Shot (which is very nice) with your plant mass it could be that you require a more flow especially lower down. Your 60cm high tank is 230l and your filter only outputs 1040l/hour whereas high tech tanks usually require 10x (manufacturers claim) flow. From the photos I can't make out your filter return method into the tank but it's quite possible a strategically placed powerhead lower down in the tank which complements your existing flow will help. I have a 230l tank also and use a AI Nero 3 for this same purpose running at 15% while CO2 is on and 1% when it is off and it works wonders.
Changing more than 50% of your water volume each week will also benefit your tank ensuring there is nothing building up to toxic levels and ridding the tank of organic waste.
I'm unsure how to calculate your Magnesium content from your dosage of the 0.8% TNC to dGH, but I'm sure adding one or two teaspoons straight after water changes should bring it more inline with 3-1 Ca-Mg ratio which is widely accepted.
All of the above are just my personal beliefs and we all know there is more than one way to skin a cat.
Cheers!

@bazz Hi - just pondering the question of my filter. With 10x spec needed, thats 2300 ltr/hr. What filter do you use on your tank? I have heard good things of Oase biomasters but the 850 (which i understand is the largest) has flow rate of 1550 l/hr - not massively different from the nominal value from my Betta. Fluval FX6 on the other hand is 2130 lt/hr. I don't want the added complication of more than one filter

 

[bazz]

Hi,
I use the Eheim 2180 which I think is now called the Eheim Professional 3 XLT which is specced at 1700 lph. When the tank was first set up it seemed to be overkill but now all the plants have grown in it is about perfect. I'm using a glass lily pipe return but found to have dead spot directly underneath this in the corner of the tank. This was remedied (as above) with the Nero which moves a large volume of water all around the tank without creating a vortex.
Reading your reply above I noted you are using a spraybar return which completely alters the flow dynamics from which I was advising in the earlier post. What I would look out for is that all parts of all plants (obviously not Buce, Anubius etc) are gently swaying in the flow and that nutrient/CO2 rich water is flowing down the front of your tank, back along the substrate and passing through the base of those stems, assuming your inlet is in the bottom back corner. Additionally you can crush a small amount of fish flake, administer it in various parts of the tank (not all at once) to discover your flow pattern and ensure you have no dead spots and all parts of the tank are being serviced.

@bazz Hi - just pondering the question of my filter. With 10x spec needed, thats 2300 ltr/hr. What filter do you use on your tank? I have heard good things of Oase biomasters but the 850 (which i understand is the largest) has flow rate of 1550 l/hr - not massively different from the nominal value from my Betta. Fluval FX6 on the other hand is 2130 lt/hr. I don't want the added complication of more than one filter

Please do not be tempted to buy any extra equipment on my say, your problem may well not be related to the advice I have given, but in my experience problematic high tech aquariums with sufficient CO2, light, nutrients and the removal of organics (50%+ water changes) are 9 times out of 10 suffering from imperfect flow and distribution.
Cheers!

 

[LFNfan]

Hi

I have similar (worse) black lining / patches on my anubias. I think it's algae.

• Rubbing with thumb and finger makes very little impact but light brown coloured water appears on fingers after rubbing.
• When the nerites find the stuff, the leaf is sparkly clean within the day.
• The stuff comes off when lightly rubbed with alcohol (I've only done that once, as an experiment)
• The plant itself is growing fine.

I have no CO2 and it only affects my (single) anubias so I am happy to live with it and even happier when the snails clean it off!

 

[TrevC]

Hi All - I am progressing with the tank issues and Epsom salts dosing and will post some pictures next week. I think that the black lining is not getting any worst but certainly not clearing up. Should I be removing any badly affected leaves and stems as I assume it does not just 'go away'. I have 3 nerites but they can only do so much I suppose.

 

[_Maq_]

if using charcoal it needs to be replaced periodically, otherwise the things it has absorbed will start leaking out of the charcoal again.

This is not quite correct.
Activated carbon traps many compounds, largely organics. But its affinity for various compounds is different. Generally, in the beginning, when the AC is "empty", it traps everything. Later on, it may release some compounds for which it has low affinity and trap compounds for which it has higher affinity instead. But in principle (unless physico-chemical conditions change significantly) AC never releases what it has trapped before.
Remember, regenerating ("cleaning") AC requires treatment in very high temperature and pressure. Unless you treat it like that, it remains "dirty" - in other words, it does not release what it had trapped.

 

[Hufsa]

This is not quite correct.
Activated carbon traps many compounds, largely organics. But it's affinity for various compounds is different. Generally, in the beginning, when the AC is "empty", it traps everything. Later on, it may release some compounds for which it has low affinity and trap compounds for which it has higher affinity instead. But in principle (unless physico-chemical conditions change significantly) AC never releases what it has trapped before.
Remember, regenerating ("cleaning") AC requires treatment in very high temperature and pressure. Unless you treat it like that, it remains "dirty" - in other words, it does not release what it had trapped.

Thanks for clearing that up Maq

 

[TrevC]

Hi - so I have been dosing with Epsom salts for the last few weeks and monitoring the black left edges:

1. The wavy look on the left crypt and some other plants seems unaffected - so maybe it is not to do with Magnesium
2. The Black leaf edges do not seem to be getting any worse - but not going away - such as on the S Repens on separate pic.

I had a chat with the guys at Aquarium Gardens and have subsequently upped my CO2. Since I've also reached the end of my bottle of TNC, I've got some APT Complete 3 to try.

Subsequent to taking these pictures I've done some pruning - including snipping off some of the worse black edges leaves (mainly Anubias). Its not treating the cause but will be interesting to see if the black leaf edges come back. Similarly I also tried (for the first time) a 5 min 7.5% bleach bath on some of the plants. Worked well on the S Repens and Anubias. Less well on Alternanthera and Hyg Siamensis.

Finally, I continue to ponder about the filter (a Betta 1050UV) and flow/distribution - not much waving around of plants unless directly below the spray bar. In the short term I have added a Voyager Nano 2000 powerhead - seems have done the trick. On the filter, I want to keep my existing inline CO2 diffuser which limits choice for filters with nominal flow of about 2000 lph - but that is another debate /forum.

Again all advice welcome.

 

[Hufsa]

1. The wavy look on the left crypt and some other plants seems unaffected - so maybe it is not to do with Magnesium

Just to be clear, we are talking about the wavyness of the green pattern on the leaf, and not a dimensional waviness of the leaf structure itself. In another way to say it, the uneven color not the leaf surface.
I just wanted to note that so theres no misunderstanding.

Since you've been using the Epsom salt ( Magnesium / Mg) and the leaf pattern in the old leaves havent improved like it would with a mobile plant nutrient, that brings us to my second candidate based on likelihood, Manganese (Mn), the trace nutrient.
This one can also cause this particular pattern of chlorosis.

Im seeing the chlorosis pattern still faintly on your new leaves of Staurogyne. Some seem a bit greener in new leaves, but a little more to be done still.
This species is a great indicator plant as its leaves are relatively easy to read.

Some of your other plants also look better, like new growth on anubias and Limnophila.
So keep doing what you have been doing so far, it was a step in the right direction.

Since I've also reached the end of my bottle of TNC, I've got some APT Complete 3 to try.

This will be interesting to see. If you were to continue with TNC I would have liked to look further into the Manganese content in that, but since you're switching fertilizer I think the best course of action will be to use the new fert for a handful of weeks and then report back with pictures of the plants when they have grown some with that one.

Again all advice welcome.

Other than my previous thoughts I support continuing to look into ways to improve plant growth in your tank. The black leaf edges should disappear when the plants are doing well enough 😊 Happy plants, happy tank