Frogbit damages and decay

[LMuhlen]

I have this spare tank which has been a plant farm, then an experimentation tank, then a quarantine, and now is a little of all of those at the same time. In practice, right now it is a tank with very old aquasoil, plants that are well established, but never in the best of conditions, lots of relentless green thread algae, yeast CO2, fertilized in the same way as my main tank with home mixed macros and commercial micros + iron.

The thing is that in this particular tank, the frogbits always die, and always the same way. I add healthy looking plants from the other tanks, and from the moment they touch this tank's water, all new leaves grow filled with holes. Old leaves remain unaffected. Other floating plants look OK...

Now, I can hear @dw1305 's voice in my head, obviously fictitious, saying that it must be an immobile nutrient, most likely iron. And because of this, I have been very careful to add iron to this tank in a rigid schedule for at least 2 months now. I also had a week when I added extra calcium and another when I added extra potassium, with no changes at all.

The tank's water is very soft, KH measured between 0.5 and 1.0ppm, water is mildly acidic. I dose the bottle's recommended dose for micros and add an extra 0.1ppm of Fe divided in three weekly doses. I don't know for sure what kind of Fe it is, but it is probably gluconate. Even though the plants in the tank aren't all that well, I don't see any clear signs of deficiencies like chlorosis.

At some point I discovered that the expiration date on my iron bottle was over an year past, so I happily bought a new bottle, from a different brand, and thought that was it, but unfortunately it didn't change anything.

In this picture, a recently added frogbit that has grown its first leaf in this tank, and one that has been there for a long time...

 

[hypnogogia]

Do you dose it the same as your main tank, where the frogbit comes from? How different are the water parameters between this tank and your others?

 

[dw1305]

Hi all,

Now, I can hear @dw1305 's voice in my head, obviously fictitious, saying that it must be an immobile nutrient, most likely iron.

No, that is my voice, I'm just shouting really loudly across the Atlantic.

It is definitely an issue with an immobile nutrient, and I quite often see this <"reticulated net-like chlorosis"> in <"my own plants">. Have a look at @jameson_uk 's thread <"Frogbit taken a turn">, there are some very similar looking plants in that thread.

We have had <"at least one thread"> where the issue was lack of plant available manganese (Mn), but these were with a a slightly abnormal set of water parameters, with an unusually pure water supply.

I think other than that it has always been an iron (Fe) availability issue.

cheers Darrel

 

[LMuhlen]

Do you dose it the same as your main tank, where the frogbit comes from? How different are the water parameters between this tank and your others?

I forgot to mention, one of the previous experiments with this tank was to use my main tank's water as the source for WCs. And I still do that, mostly because it makes things simple. So they both have the same water, but this tank gets it more "seasoned" after a week in the main tank. I do add ferts normally to this tank, so if anything, there should be slightly more of them. Unless it is something that I don't dose and that comes from tap water, then it could be something that the main tank consumes. I don't add extra magnesium to this tank, but the main tank gets ~7ppm measure for the volume changed. They both get a leaner dose as of several months ago. I don't measure stuff all that much, but this tank gets less CO2 than the main tank.

What amazes me is that this supposed deficiency is very extreme on frogbit, they instantly start dying when added to this tank, while the other plants are looking decent.

@dw1305 My micro mix adds standard amounts of Mn... Should I just add more iron? More micros? Get a priest?

 

[Bradders]

 

[dw1305]

Hi all,

was to use my main tank's water as the source for WCs. And I still do that, mostly because it makes things simple. So they both have the same water, but this tank gets it more "seasoned" after a week in the main tank. I do add ferts normally to this tank, so if anything, there should be slightly more of them.

That does sound strange.

Unless it is something that I don't dose and that comes from tap water, then it could be something that the main tank consumes.

That is a distinct possibility, a nutrient that is either consumed, or <"precipitates out">, in the main tank. Unfortunately we are back in to <"Donald Rumsfeld territory"> for <"which nutrient">, other than it is <"an immobile nutrient">, and we can be sure of that because deficiency symptoms manifest straight away in the new leaves.

I'd be really surprised if it wasn't iron (Fe) deficiency, but we don't know.

Calcium (Ca) might be another possibility? But I'd be surprised if it was the culprit.

. I don't add extra magnesium to this tank, but the main tank gets ~7ppm measure for the volume changed

It won't be a magnesium (Mg) deficiency, purely because magnesium is highly mobile within the plant, and can be shuffled from old to new tissue.

What amazes me is that this supposed deficiency is very extreme on frogbit, they instantly start dying when added to this tank,

That is what you get when an immobile nutrient becomes <"Liebig's limiting nutrient">, it is like <"turning off a switch"> (like the Bacopa below, where we have on - off - on). With the more mobile nutrients plants can both <"store them for a rainy day"> and continually shuffle them to younger tissue.

but this tank gets less CO2 than the main tank.

Not CO2, floating plants have access to 426 ppm CO2 <"Global Monitoring Laboratory - Carbon Cycle Greenhouse Gases">.

My micro mix adds standard amounts of Mn...

Almost certainly not manganese (Mn).

Should I just add more iron?

It would need to be "plant available", the safest options are either <"FeDTPA"> or <"FeEDDHA">, although FeEDTA maybe all right <"Plant deficiencies and the Fe Experiment">. After I'd added the iron chelate I'd be looking for a fairly rapid <"flush of green algal growth"> before the Frogbit improved.

Personally I use FeEDTA, because I have soft rainwater, if I had to use our tap water (about 17 dGH & 17 dKH) I'd use FeEDDHA and @Craig Matthews & @Zeus. 's <"pink tint">.

cheers Darrel

 

[Wookii]

Just to check you're not dosing any kind of Glutaraldehyde based product in this tank are you? I've seen frogbit decay like that in response to glut.

 

[LMuhlen]

Just to check you're not dosing any kind of Glutaraldehyde based product in this tank are you? I've seen frogbit decay like that in response to glut.

Negative, only things that go in this tank are potassium nitrate, potassium phosphate, commercial micro mix and iron supplement.

I guess my next step is to try and figure out what kind of chelation they use in this iron bottle. It is strange though, because I use the same iron on my main tank.

In reality I should just start doing normal water changes in this tank to see if it improves.

 

[hasan66]

I have this spare tank which has been a plant farm, then an experimentation tank, then a quarantine, and now is a little of all of those at the same time. In practice, right now it is a tank with very old aquasoil, plants that are well established, but never in the best of conditions, lots of relentless green thread algae, yeast CO2, fertilized in the same way as my main tank with home mixed macros and commercial micros + iron.

The thing is that in this particular tank, the frogbits always die, and always the same way. I add healthy looking plants from the other tanks, and from the moment they touch this tank's water, all new leaves grow filled with holes. Old leaves remain unaffected. Other floating plants look OK...

Now, I can hear @dw1305 's voice in my head, obviously fictitious, saying that it must be an immobile nutrient, most likely iron. And because of this, I have been very careful to add iron to this tank in a rigid schedule for at least 2 months now. I also had a week when I added extra calcium and another when I added extra potassium, with no changes at all.

The tank's water is very soft, KH measured between 0.5 and 1.0ppm, water is mildly acidic. I dose the bottle's recommended dose for micros and add an extra 0.1ppm of Fe divided in three weekly doses. I don't know for sure what kind of Fe it is, but it is probably gluconate. Even though the plants in the tank aren't all that well, I don't see any clear signs of deficiencies like chlorosis.

At some point I discovered that the expiration date on my iron bottle was over an year past, so I happily bought a new bottle, from a different brand, and thought that was it, but unfortunately it didn't change anything.

In this picture, a recently added frogbit that has grown its first leaf in this tank, and one that has been there for a long time...
View attachment 221088

Could you please specify which iron dose you used here? edta? dtpa? I learned that high doses of manganese such as EDTA chelated iron are consumed quickly. Therefore, if you are using soft water, if your iron is EDTA-based, try reducing the manganese rates.

 

[hasan66]

I used to use 0.06ppm EDTA and 0.04 ppm dtpa iron. I always observed chlorosis in my tank with manganese 0.067ppm. Currently, when I use manganese between 0.016 and 0.025, I observed that the colors are better, but this is only in my own tank, it may be the opposite in other tanks.

 

[hasan66]

0.1ppm iron 0.067ppm manganese

0.1ppm iron 0.016ppm manganese

 

[RickyV]

I am starting to see this issue in my frogbit as well. Strangely my red root floaters look completely fine. However on my frogbit It seems to be affecting older leaves. I am suspecting magnesium because it is the only recent variable I've changed. Well I also reduced calcium recently but that seems unlikely.

My anubias old growth are showing dark veins.

 

[dw1305]

Hi all,

I am starting to see this issue in my frogbit as well..... I am suspecting magnesium because it is the only recent variable I've changed

Is this resolved? It is not a colour pattern I've ever seen on my Frogbit.

My anubias old growth are showing dark veins.

Magnesium (Mg) deficiency is likely.

cheers Darrel

 

[RickyV]

Is this resolved? It is not a colour pattern I've ever seen on my Frogbit.

I believe it is. For a few weeks I was experimenting with 3 ppm Mg after 30% WC and after increasing it back to 5 ppm after the WC they look a lot better. RO is the source water. This is the frogbit right now.

What is your opinion the new leaves health? How green are they supposed to come in for them to be considered healthy?

But I am now interested in doing an experiment with frogbit where I can experiment on removing one nutrient at a time to see what each deficiency looks like. Just to have a reference with pictures of what each deficiency looks like on the frogbit.

 

[LMuhlen]

As an update to this thread, my issue remains unresolved. I have tried for a week or two to individually boost each nutrient that I suspected could be involved, but still nothing.

I have done weeks for:
Iron
Micro mix
Calcium
Potassium
Phosphorus
Macro mix
Nitrogen (urea)

I have done a week doing an extra large standard water change with tap water, just to remove the uncertainty of my unusual maintenance regime for this tank. I'm not sure if I have done magnesium... I forget.

The tank is going bad fast. Plants are stunting and melting. This week the nymphea, which was fine all this time, lost all of its leaves. Possibly the urea dose was a bit too much.

The whole tank is going to be remade soon, but I want to discover what's wrong with the frogbit before doing it.

My first theory was that the difference between this tank and the blackwater tank where the frogbit is doing great was the light. The strong light in this tank was pushing the plant to grow and then it would be missing something. Since I have tried to add all sorts of things, now I'm thinking that maybe this isn't the case. So this week's experiment was to place a floating pot with only tap water in the tank and add frogbit to this pot. This way, it receives the same light as the others, but without being in the same water. We'll see. I added a healthy frogbit from the black water tank, and a terribly unhealthy frogbit that has been in this tank for a few weeks.

I'm starting to consider the idea that there is something that accumulated to toxic concentrations.

 

[dw1305]

Hi all,

What is your opinion the new leaves health?

Those look really healthy. Mine are never as green as that, possibly because they are always <"slightly starved of nitrogen (N)">.

But I am now interested in doing an experiment with frogbit where I can experiment on removing one nutrient at a time to see what each deficiency looks like.

It would be interesting. You should get an instant response when a <"non-mobile nutrient"> is turned off, but it is a longer process, and more tricky to work out, with the mobile nutrients, which the plant can constantly recycle to newer leaves.

cheers Darrel