Blackening/Browning of leaves

[TwoFace99]

(Disclaimer)Hello, I recently made a post about some concerns with my aquarium plants, and I didn’t really get a response, so I’m posting again if that’s not an issue. 

Recently, I couldn’t help but notice my Moneywort/Bacopa Monnieri older leaves’ are turning black/brown with some of them curling downward. I had this issue before (with different plants) and it was suggested to me that this could be a magnesium deficiency. I use to dose Equilibrium to correct the Mg concentration of my tank, but after a while, the GH would easily spike up to 18dGH with only 1 1/2 teaspoons of the product, despite reading 12dGH after a WC. I purchased these Bacopa in late April, and didn’t have this issue appear any sooner than a week. They have grown a lot despite being slow growers. 
Also, one of my Sword plants, Corymbosa Angustofolia, and Bucephalandra Lamadau Mini seem to experiencing the same blackening of leaves. In addition, the Sword plant in question seems to be growing stunted new growth like my previous Amazon Sword that was growing in the exact same spot.
Not to mention, my Ludwigia Natans Super Red are losing new growth soon after they sprout from the top of the stems. What should I do?

Water parameters:

pH: 7.8

Ammonia: 0ppm

Nirite: 0ppm

Nirate: 20ppm (Mainly Easy Green)

KH: 8dKH

GH: 12dGH

Also, I dose 2 cups of Flourish Iron 3x a week (Monday, Wednesday, and Friday).

[Tony s]

On 6/12/2024 at 5:27 PM, TwoFace99 said:

it was suggested to me that this could be a magnesium deficiency.

Yeah. I really doubt you have a magnesium deficiency. You have hard water. Calcium and magnesium are the two biggest factors in hard water. It’s more likely you have a potassium deficiency. Most aquariums have a potassium deficiency. As potassium binds to most soils and doesn’t enter the water stream. We have the same issue when growing crops. Only we can add it to our soil 

The new easy potassium from coop might be very helpful to you 

[TwoFace99]

On 6/12/2024 at 6:06 PM, Tony s said:

Yeah. I really doubt you have a magnesium deficiency. You have hard water. Calcium and magnesium are the two biggest factors in hard water. It’s more likely you have a potassium deficiency. Most aquariums have a potassium deficiency. As potassium binds to most soils and doesn’t enter the water stream. We have the same issue when growing crops. Only we can add it to our soil 

The new easy potassium from coop might be very helpful to you 

I thought potassium deficiency has to have pinholes littered throughout the older leaves of the plants? 

[Tony s]

that is a symptom. but almost all aquatic systems are deficient in potassium to some degree. If it binds to the soil, it can't get in the water. where we have to worry about excess ammonia and phosphate getting from the crops to the water table. we don't worry about potassium. it doesn't move 

Edited June 12 by Tony s

[Tony s]

the other thing about using the equilibrium. your calcium and magnesium don't evaporate. so, if you're adding it to every water top off, you're actually increasing your gh constantly. for my ro, I add only enough equilibrium to increase the water I'm changing to the desired level. ie... if I make a 30g tote of ro water I add enough to change the tote to the desired gh. if my gh is too high already, sometimes I don't add it at all. and I never add it to top offs

If you really want to know what you have and don't have, they make water drop test of almost every mineral you could have. a couple time use those and you could really dial in what you actually need

[TwoFace99]

On 6/12/2024 at 6:29 PM, Tony s said:

that is a symptom. but almost all aquatic systems are deficient in potassium to some degree. If it binds to the soil, it can't get in the water. where we have to worry about excess ammonia and phosphate getting from the crops to the water table. we don't worry about potassium. it doesn't move 

That makes sense, and I’m assuming that means Potassium is an immobile nutrient?

On 6/12/2024 at 6:35 PM, Tony s said:

the other thing about using the equilibrium. your calcium and magnesium don't evaporate. so, if you're adding it to every water top off, you're actually increasing your gh constantly. for my ro, I add only enough equilibrium to increase the water I'm changing to the desired level. ie... if I make a 30g tote of ro water I add enough to change the tote to the desired gh. if my gh is too high already, sometimes I don't add it at all. and I never add it to top offs

Yea, I had that GH issue a while back, which is why I stopped using Equilibrium, and everything was settling until this problem occurred.
For instance, the Bacopa Monnieri, would I simply just clip off the damaged portions and hope the the new growth doesn’t go down the same path once they are considered new growth as well? I ask, because the Bacopa Monnieri looks somewhat salvageable, but I have no clue about my Ludwigia Natans or Bucephalandra.

[lefty o]

im not the expert around here, but to my eyes i see all the leaves with problems are victims of green spot algae. green spot grows on them, and kills off the leaf. need to get that under control better.

[Tony s]

On 6/12/2024 at 7:52 PM, lefty o said:

my eyes i see all the leaves with problems are victims of green spot algae. green spot grows on them, and kills off the leaf

i agree with that. but helpful to that is to get the plants up and growing faster

 

On 6/12/2024 at 7:45 PM, TwoFace99 said:

I’m assuming that means Potassium is an immobile nutrient

Yes. In the soil profile it may move only a couple of inches a year. even under excess conditions. If it doesn't move. it doesn't run off into streams and it doesn't enter the water table. soil is negatively charged; potassium is positively charged. so they bind

 

On 6/12/2024 at 7:52 PM, lefty o said:

im not the expert around here

yeah. on aquatic plants and algae, me neither. but understand relatively well nutrient deficiencies

Edited June 13 by Tony s

[TwoFace99]

On 6/12/2024 at 6:52 PM, lefty o said:

im not the expert around here, but to my eyes i see all the leaves with problems are victims of green spot algae. green spot grows on them, and kills off the leaf. need to get that under control better.

I forgot to include that my phosphate levels are consistent at 1.0mg/L, and I did add half a capful this past Monday ( 50% water change). From what I have read about green spot algae, they are more or less caused by inadequate levels of NPK, but more so phosphate. I’m assuming I would have to dose more of phosphate or preferably both phosphate and potassium. 

[Tony s]

On 6/12/2024 at 7:45 PM, TwoFace99 said:

For instance, the Bacopa Monnieri, would I simply just clip off the damaged portions and hope the the new growth doesn’t go down the same path once they are considered new growth as well? I ask, because the Bacopa Monnieri looks somewhat salvageable, but I have no clue about my Ludwigia Natans or Bucephalandra.

yeah, that's above my paygrade. I'm still learning aquatic plants🤣 If you wanted help with garden plants or crops I could do that better. or even water chemistry in general. ph gh kh, those I can do. But I could more easily tell you what to do for your tomatoes and corn than your Buce

Edited June 13 by Tony s

[TwoFace99]

On 6/12/2024 at 7:02 PM, Tony s said:

yeah, that's above my paygrade. I'm still learning aquatic plants🤣 If you wanted help with garden plants or crops I could do that better

No, I appreciate whatever help I can get. This aquarium has experienced quite a lot of turmoil with plant health, since I started last October. If what you’re saying is true, then I have experienced every nutrient deficiency, outside of nitrogen or manganese within this aquarium alone. Granted, this is my first planted aquarium, since re-entering the hobby.

Edited June 13 by TwoFace99