Indicator Plants

justinstewart

justinstewart

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I hate the saying "grow the plants." What do you think I'm trying to do, kill them? It takes a lot of experience to read plants.

every person that has a planted tank should have the basic indicator plants. Ie fine leaved plants like Rotala wallichi, bangladish and Dwarf Hairgrass for Iron. Ludwigia pantanal for Nitrates, and the list goes on and on. As Dennis Wong and Tom Barr say all the time watch your plants!!!
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Saying watch your plants is great, but if you dont know what your looking for, it doesn't help.

How do you decide or more importantly, what indicators do you see when deciding the extra doses?
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Thats a good question. Macros usually if a tank is really full like the Dutch is now. Or if a picky species start to pout a little bit, say a few tulu get stunty, wallichii types, anything that stunts really, or say the center of syns get a little pale which they are prone to do. A little more macros almost always fixes it


Micros can usually just tell when certain plants get a little pale. Stunting can be low micros too. Generally ime, stunting with poor color (pale) is usually low macros. Stunting with good color is usually low micros. Stunting with intensely deep color is usually too much micros

I know thats not a very definitive answer but I really dont have one. Kinda just look at the whole picture and see what plants are doing what
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Sorry for the rant, but I think this poses an interesting question that can help people.

Do you have any favorite indicator plants? How do you read them and what do they tell you?
 
The legend, @Burr740, told me on another forum that having nice straight non-wavy leaves on Alternanthera Reineckii is a good indication that my micros are good.
 
Worth mentioning is the Duckweed index What is the “Duckweed Index” all about? developed by Darrel on UKAPS. I believe it makes a lot of sense, but I am not sure how many are actually using it in the hobby.

I am using Rotala Wallichii as indicator plant. In my tank it is the canary in the coal mine for any instability, for example CO2. It shows its unhappiness by stunting, or at least this is what I believe, and will pick up growth when it’s happy again. Replanting often leads to stunting as well, so that may be confusing. I am interested to hear if others have same experience with Wallichii.

Probably another real good indicator are various type of algae, or rather their absence from the tank.
 
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Yugang said:
Worth mentioning is the Duckweed index What is the “Duckweed Index” all about? developed by Darrel on UKAPS. I believe it makes a lot of sense, but I am not sure how many are actually using it in the hobby.

I am using Rotala Wallichii as indicator plant. In my tank it is the canary in the coal mine for any instability, for example CO2. It shows its unhappiness by stunting, or at least this is what I believe, and will pick up growth when it’s happy again. Replanting often leads to stunting as well, so that may be confusing. I am interested to hear if others have same experience with Wallichii.

Probably another real good indicator are various type of algae, or rather their absence from the tank.
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I think the Duckweed (Frogbit) Index is not a great fit for most higher energy tanks, but if you can practically keep floaters it's a great idea. I am trying to use it in my big tank, but floating plants don't get along well with spray bars, so that's annoying. I imagine if you use tons of fertilizer throwing out the extra plants would be a part time job, and if you are trying to pump a lot of light, floating plants create unwelcome shade. So there are many situations where it doesn't work.

But in my tanks with HOBs and less energy it's working great! It's really nice to be able to look and immediately see if I'm bottoming out of nitrogen or iron, both of which can be an issue for me if I slack on water changes. And floating plants are a great way to stabilize a new tank.
 
I am not putting Duckweed anywhere near my tank. That thing can get out of control.

I too often use R. wallichii as an early warning sign. To me, that is what indicator plants mean - an early warning that something is off. I've never successfully found a plant that can individually tell me my micros are off or that Fe is low. For that, all of the plants tend to tell me. Probably because I've been using stems almost exclusively for such a long time.
 
I really like the duckweed index. I have my floaters exposed to the most light and CO2 so I'll see any problems on them before I see them in the tank. I use both frogbit and red root floaters. The RRF are especially great for seeing the nitrogen levels in the tank.Screenshot_20240623_174202_Gallery.jpg
 
@Joel Armstrong I have my way but making sure you know it isn't the only or best way. Like you, I'm still learning.

As I know what I'm dosing, my base line assumption is that I'm providing the plants with 100% of what they need to be healthy and grow well. This requires that you trust the fertilizer you are adding. This is why I roll my own and use @Burr740's micros.

The difficult part for me is finding that I am providing ENOUGH of what they need to grow well without providing TOO MUCH of it. Over time, you learn what your plants should look like when they are healthy and growing well. There's a fertilizer sweet spot, based on your aquarium's ecosystem, that you want to stay in. You can only find it over time and being patient and observant.

I usually see that some of the sensitive plants are not doing well. I then test macros to confirm they are in line with what I expect them to be. More often than not, macros are the problem because I screwed up on my math or the doser is off or something.

If the macros are fine, then I confirm CO2 level (usually OK). Then I start to think about micros. I will usually ask an expert to see if I should increase or decrease micros. Then wait and see.

I wish I could tell you that plant X turns blue if you lack Fe or red if you lack Boron or purple if you lack something else. Well, lack of Fe is pretty obvious but you get my point. You focus on health first, usually of a sensitive plant, then work down your checklist.

Sorry about the extensive explanation of my process. An indicator plant is just part of how I drive my aquarium.

In fact, now that I don't have any indicator plants in my aquarium, it will be interesting to see how I adjust.
 
This is a great topic. It can be hard to nail down the specifics because so many factors can cause the same issues. Here's a few things I trust to mean a certain thing

Fe/Micros
Probably the toughest one of all because too much and too little can look pretty much the same. And you do have to be careful not to have either one

Alternanthera varieties, all of them: Gnarly twisted leaves when micros are too high. You can set your clock by this. The kicker is low macros can cause the same thing. So before you look at micros make sure theres enough macros available, either at the roots or in the water

Sensitive Rotalas like macrandra are highly dependent on having the right micro levels. Stunting with good color = too much. Stunting with poor color = not enough. And stunt they will if your micros are off much

Pale tops on green plants = not enough

Proserpinaca palustris (mermaid weed) is the absolute fastest plant Ive ever seen go south with too much Fe/micros. The tops completely shrivel up in just a day or two

Potassium
Literally any stem that requires co2, especially Pogostemon, Limnophila and L inclinata varieties - shrinking stunted tops

Hygrophila varieties are the first and fastest indicators of low K. They shrink at the tops and the old leaves quickly show pinholes or degrade completely

K is also a tough one to nail down because low NO3 can cause similar issues

PO4
Big leafy greens, starting at the 2nd or 3rd node from the top, the leaves turn pale and degrade. I havent seen this specific response from anything else so when it happens I know its time to raise PO4

CO2
We all know poor co2 can cause all sorts of issues. But one indicator that always means co2 is low in my tanks is delicate Myrio varieties like Mini and Gold melt at the bottom stem. Other stems can eventually do this with low co2, and also when macros (esp PO4) are low. But one of the first indicators that co2 is low even when no other problems exist is these myrio melting stems at the bottom

I'll probably think of some more...
 
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I recall @Burr740 telling me Spatulata stems going necrotic and separating was a good indicator for low PO4. When this happened to me, my PO4 was low.
 
Unexpected said:
I recall @Burr740 telling me Spatulata stems going necrotic and separating was a good indicator for low PO4. When this happened to me, my PO4 was low.
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Staurogyne spatulata is one of those big leafy greens I was talking about. Its also the species I first noticed a specific reaction to low po4. The first time I put it together I was breaking in new aquasoil. It was always the first plant to act up, other big greens soon followed with the same symptoms
 
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