Lobelia cardinalis dark spotting/patching?

[dw1305]

Hi all,

Still have this discolouration on the leaves (has spread a bit on the same plant).

Can we have another photo?

cheers Darrel

 

[JBFUK]

Sure. If you look at the lower leaves it looks like they might be rotting around the edges?

 

[JBFUK]

No ideas at all? Another water change on Saturday so I again had a go at rubbing this off of a leaf. It really doesn't seem like any type of algae based on the fact that I can't shift it at all. Surely it must be a lack of or excess of some nutrient? Could it be related to light spectrum or the lights being on for too long?

Even looks like it may have started developing on another plant too 🙁

 

[Witcher]

No ideas at all?

I'd look at the levels of Cl/Na in you tank, they are probably too high.

https://www.pthorticulture.com/en/training-center/role-of-sodium-and-chloride-in-plant-culture/

 

[JBFUK]

Hmm, even though this issue began while I was purely using RO water with Seachem minerals?

 

[Witcher]

Hmm, even though this issue began while I was purely using RO water with Seachem minerals?

I must admit that's quite surprising to me, I had similar symptoms on Lobelia and Alternanthera when using hard tap water (packed with Cl and Na) - once I've switched to RO (re-mineralised, with only tiny amounts of Na/Cl), dark edges were gone.

 

[JBFUK]

Based on previous advice earlier in this thread I switched from RO with Seachem Equilibrium and buffers to a 50/50 mix of RO and tap water. The only photos I've found elsewhere so far which look a lot like mine are here (http://www.aquariumadvice.com/forums/f24/whats-wrong-with-my-plants-129681.html) and the general opinion seems to be that he needs to add more ferts.

Punching my numbers in to https://rotalabutterfly.com/nutrient-calculator.php suggests I might not be using enough ferts. I wanted to be careful not to over do it so I've been using half of the dose suggested on the bottle, divided in to two weekly applications. Think I'm going to double up on everything this week and see how it goes. Not sure whether the affected leaves would recover at all of perhaps it will just stop getting worse?

 

[Witcher]

Not sure whether the affected leaves would recover at all of perhaps it will just stop getting worse?

If it's even a small necrosis, no chance they will recover, only can get worse (tissue in those areas is dead).

Punching my numbers in to https://rotalabutterfly.com/nutrient-calculator.php suggests I might not be using enough ferts.

Hmm, assuming you have lightly planted tank and Nitrate between 10-20ppm I'd rather say it's more than enough, with the amounts of plants I see on you photos I'd never add more than 5ppm of NO3 weekly (and other ferts accordingly)

 

[JBFUK]

The tap water I'm now cutting my RO with (after being advised to stop using Equilibrium and associated buffers) has around 20ppm of Nitrates. So using a 50/50 cut with RO that's giving me around 10ppm plus whatever is generated in the tank from fish waste etc, so I figure I don't need to add any nitrogen.

In terms of my dosing as I said before I'm using very low levels. Currently I dose the following in an aquarium with ~32L of water:

Flourish Complete - 0.3ml twice a week (0.6ml)
Flourish Potassium - 0.64ml twice a week (1.28ml)
Flourish Iron - 0.4ml twice a week (0.8ml)
Flourish Phosphorus - 0.75ml twice a week (1.5ml)

The calculator I liked to above, set to EI Low Light/Weekly dosing suggests I should be dosing in the following over a week:

Flourish Complete - 1ml (to achieve 0.1 ppm FE)
Flourish Potassium - 6.7ml (to achieve 10 ppm K)
Flourish Iron - 0.32ml (to achieve 0.1ppm FE)
Flourish Phosphorus - 8ml (to achieve 1ppm PO4)

Then looking at the 2 Hour Aquarist website (https://www.advancedplantedtank.com/fertilisers-how-to.html) he provides some guidelines on target ppm for various elements. If I took the recommendation for those which he considers to be dosing 'lean' I'd be looking at using the following:

Iron/Trace 0.3ppm - Flourish Complete 2ml / Flourish Iron 0.32ml
Potassium 15ppm - Flourish Potassium 10.05ml
Phosphates 7ppm - Flourish Phosphorus 56ml
Nitrates 7ppm - nothing to add, already abundant
Magnesium 5ppm - ????

So it really looks like I'm good or even a little overdosed on Iron and nitrogen but for Potassium and Phosphates I'm adding way less than I should be, even if I were being conservative and adding half the amount he suggests.

Magnesium is a concern too. I believe I was previously getting this from remineralising with Equilibrium but now that I'm cutting my RO with tap water instead I don't think I have enough. The latest water quality report on my water company's website is from 2018 and shows 3mg/L of Mg in the supply. That's an average based on seven reading over the year. Lets presume it's still valid it means I'm getting 1.5mg/L once cut with my RO water. Where do I get the extra 3.5mg/L of Mg from? Seachem don't sell a 'Flourish Magnesium' - I guess because they want you to be buying and using Equilibrium to remineralise.

Do you not think based on the above that I'm significantly under-dosing on Potassium and Phosphates?

 

[sparkyweasel]

Where do I get the extra 3.5mg/L of Mg from?

Epsom Salts, cheap and readily available.

 

[dw1305]

Hi all,

has around 20ppm of Nitrates. So using a 50/50 cut with RO that's giving me around 10ppm plus whatever is generated in the tank from fish waste etc, so I figure I don't need to add any nitrogen.

I wouldn't make any assumptions. Your tap water NO3- level will change throughout the year. In the winter, when the farm animals are inside, it rains a lot and arable crops aren't getting any fertiliser, levels will be a lot lower. You usually get a nitrate spike in spring once the grass etc is growing again. Farmers use a cumulative temperature index as an indication of when to start adding nitrogen to their crops. You get these variations even in large conurbations, because surface and groundwater travels considerable distances.

Epsom Salts, cheap and readily available.

Personally, even for a small tank, I'd use dry salts rather than branded fertilisers. I'm often asked if a particular fertiliser is "any good" or whether "brand x is better than brand y", and I always tell people that every potassium (K+) ion is the same as every other K+ ion, they don't "know" that they came from ADA or Seachem's finest.

So it really looks like I'm good or even a little overdosed on Iron

Iron is a little bit different to most nutrients. When you add potassium nitrate (KNO3) you know it has gone into solution as a 1:1 ratio of K+ and NO3- ions, and that those ions will remain in solution. It is different with iron (Fe), nearly all its compounds are insoluble and whether it is plant available depends on the hardness and pH of the water <"and the chelator"> used.

Because water testing can be problematic, I advise people to use <"plant health"> (in a floating plant to remove light and CO2 deficiencies from the equation) as an indicator of nutrient level. It still needs a bit of interpretation, <"but it works fairly well">.

Have a look at <"Slightly sad.........">.

cheers Darrel

 

[JBFUK]

Epsom Salts, cheap and readily available.

Thanks, I have a small amount in the bathroom cupboard, will mix a solution and start dosing a little as well as upping all my other dosing. Nobody has actually confirmed that the numbers I posted before look sensible and that I am under dosing currently, but that seems logical to me. Hopefully someone will help me confirm that I've not miss-calculated.

I wouldn't make any assumptions.

I'm not, as we discussed earlier in this thread my drop testing shows at least 20ppm of Nitrates in my tap water, which was why I had started using RO in the first place. Now I'm cutting the RO 50/50 as you advised, there will be at least 10ppm in my tank water, slightly more the last time I tested it. Very little animal farming in this county but I imagine farmers fertilise winter crops etc so I will test it every so often.

Personally, even for a small tank, I'd use dry salts rather than branded fertilisers.

So this is an interesting point. I found and started reading James' Planted Tank website last night. Very interesting and a good source of information for a beginner like me. Now the sad thing is that the supplier he links to for the dry salts no longer lists any of the recommended dry salts on the website. I contacted the supplier and he said that unfortunately due to 'the current climate' and no longer being able to send potassium nitrate via the post, he has had to stop supplying the salts. So it seems the terrorists have spoiled this for everyone (so they won?) - I hope you have a good stock of these things saved up. If you know of another reliable supplier still selling these please let me know and I'll stock up before they stop selling them too.

Because water testing can be problematic, I advise people to use <"plant health">

That is what I am doing. I don't want floating weeds in my tank, but, I have been saying here for some time now that I think I have an issue due to the poor health of my Lobelia Cardinalis. That is what has led me to look closely at the nutrients and dosing that I'm currently putting in my tank.

So really I'm hoping someone with more experience than me can look at the numbers I posted above and tell me whether the proposed new dosing levels look reasonable based on those calculations/assumptions. I'm looking at increasing my weekly potassium dose by a factor of 8x and phosphorus by a factor of 37x so it would give me some peace of mind to know that those new levels are not unreasonable and I am not going to accidentally poison my tank because of some error in calculation.

 

[dw1305]

Hi all,

drop testing shows at least 20ppm of Nitrates in my tap water...........there will be at least 10ppm in my tank water, slightly more the last time I tested it

I agree there is likely to be quite a lot of nitrate in your tap water, and it is unlikely that your plants are short of nitrogen.

I'm not <"personally a fan of nitrate test kits">, but others will tell you that they can be used accurately.

What level of nitrate does it say on your water report? Water companies legally have to test for nitrates and they have pretty high tec. labs.

contacted the supplier and he said that unfortunately due to 'the current climate' and no longer being able to send potassium nitrate via the post, he has had to stop supplying the salts

I understand there are issues with obtaining nitrates, due to their potential use as explosives.

You can actually buy food grade potassium nitrate (KNO3) via Amazon etc. it is used for curing meat etc and is additive "E252".

That is what I am doing. I don't want floating weeds in my tank, but, I have been saying here for some time now that I think I have an issue due to the poor health of my Lobelia Cardinalis.

It is just easier to diagnose deficiencies from floating plants, I like them, but know not every-one feels the same. In hard water iron (Fe) and magnesium (Mg) are likely deficiencies, mainly because of interactions with calcium (Ca++) and bicarbonate (HCO3-) ions.

So really I'm hoping someone with more experience than me can look at the numbers I posted above and tell me whether the proposed new dosing levels look reasonable based on those calculations/assumptions. I'm looking at increasing my weekly potassium dose by a factor of 8x and phosphorus by a factor of 37x

No, you probably don't have to add that much.

As you can see from the range of values selected on different web sites there isn't a single value that constitutes the ideal dose. If you have a look at the <"Rotala Butterfly Nutrient Calculator"> even for EI you only have 1 -2 ppm PO4 as a suggested range (this was using KH2PO4 as my salt).


In diagnosing deficiencies there are just lots and lots of variables

As an analogy your football team plays well, but keeps losing "unluckily", they are never stuffed and at times look a good team, but it gets to the end of the season and they are comfortably relegated. In this case "league position" is your plant health, it doesn't lie.

cheers Darrel

 

[JBFUK]

Clearly I am lacking in nutrients, it seems that even using conservative target ppm figures, the bi-weekly doses I have been using are very low. The green patching has also started to appear on another plant in the tank - showing on the very top leaves. Also some yellowing/loss of colour. Again I tried rubbing off the dark green patches but it doesn't shift, so seems like a problem with the plants cell structure rather than algae growing on the leaves. The closest things in deficiency diagnosis charts/photos that I can see are Phosphorus and Magnesium deficiencies.

I've added an emergency dose of 3.5ppm Mg, 1.25ppm PO4 and 3.7ppm K - at this point I need to stop things deteriorating. This raised the measured TDS by around + 25ppm so it seems like the nutrients contain other elements in addition to those targeted, or the numbers are wrong?

I'm going to stop the micro dosing schedule I was running before and do some more reading/learning over the coming days.

I don't really want to use the EI method as long term 50% weekly water changes are not going to work for me. Weekly changes of ~20% will be much more achievable. Perhaps fortnightly changes of 50% would be 'ok' but I don't believe that's frequent enough if using EI methods. The PPS method seems interesting but I need to learn more about it. Daily dosing of multiple nutrients will be a pain, if I made one nutrient blend to dose daily that would be much less hassle (apart from when away on holiday etc). The only issue is I seem to remember from dipping in to basic hydroponic veg growing that you can't mix all nutrients in to one 'complete' blend as interactions between different compounds can cause specific nutrients to bond and form insoluble compounds which 'drop out' of the solution. That's why various hydroponic nutrients come divided in to 'A' and 'B' bottles.

 

[dw1305]

Hi all,

I've added an emergency dose of 3.5ppm Mg, 1.25ppm PO4 and 3.7ppm K - at this point I need to stop things deteriorating?

I think that is a good idea. They are all nutrients that are mobile within the plant, so if one or more of them was deficient you should get a quick greening and growth.

This raised the measured TDS by around + 25ppm so it seems like the nutrients contain other elements in addition to those targeted, or the numbers are wrong?

You are fine. There isn't a direct relationship between ppm you've measured and the ppm you've added, there should be but the meter actually measures electrical conductivity and then converts it to an approximate TDS reading. Some ions are better conductors of electricity than other ones.

I don't really want to use the EI method as long term 50% weekly water changes are not going to work for me. Weekly changes of ~20% will be much more achievable.

I'm not an EI, or CO2, user, in my case I'm not interested in optimal plant growth, I just want some growth. The analogy I would use is EI is a <"vegetable growing approach">, I'm looking more to grow orchids or succulents.

The only issue is I seem to remember from dipping in to basic hydroponic veg growing that you can't mix all nutrients in to one 'complete' blend as interactions between different compounds can cause specific nutrients to bond and form insoluble compounds which 'drop out' of the solution. That's why various hydroponic nutrients come divided in to 'A' and 'B' bottles.

That is right, if you want to keep everything in solution you need to acidify the solution to a a low pH. If you don't acidify the solution you need to keep the iron (Fe++) and phosphate (PO4---) ions separate. Have a look at @X3NiTH's posts in <"DIY Fertilizer Formula...">.

cheers Darrel

 

[JBFUK]

Ok so iron and phosphate separate, noted.

No real change so far. I could have said that perhaps there was a slight visible improvement today but I think that would be wishful thinking, I suppose it may take a while to see any difference. I measured the TDS around midday to see whether it had dropped (indicating nutrient uptake), it was reading around 395, then at about 7pm it was reading 410; so still really just hovering around the same sort of reading as yesterday. At 7pm the Ph was 7.4 - CO2 goes off at 6pm.

Guess I should refrain from doing anything else until I see a drop in TDS to indicate some uptake is occurring.

I noticed that the upper leaves on one of the newer plants (Tropica - Hygrophila 'Siamensis 53B'), which have started to show some of the same dark green blotching, are turning pale and translucent. My impression has been that this is the expected 'transition' from an air reared plant to underwater growth. It's been in the tank for a few weeks now and the top leaves have just about reached the surface.

Thinking on my experiences with growing tomatoes and chillis using hydroponics, the Ph is very important in terms of allowing proper uptake of nutrients. If the Ph of the nutrient solution is too high many essential nutrients are 'locked out' and cannot be absorbed by the plant leading to deficiencies even if the nutrient is abundant in the solution. I seem to remember something around Ph 5.6-6 was a sweet spot to be targeted. Does the same issue not occur in planted aquariums? I've seen reference to people noticing that their plants respond well to a low KH - but perhaps what's really going on there is that the low KH leads to a lower Ph (when the CO2 is on) and that's what's actually causing the plants to take up nutrients and respond well?

Another thought that cropped up. I have been reading a bit on DIY nutrients from dry salts, with the idea that I would want to create a mix without any nitrates, so as not to poison my fish and even more importantly shrimp. Now the opinions on what levels of nitrates are toxic (or even unpleasant) for fish and shrimp seem to be mixed, as are opinions on whether nitrates from added nutrients are really the same as nitrates from the bacteria based filter cycle. It made me think that I have not been dosing any Nitrogen at all under the presumption that any nitrogen needs are being served by the nitrates showing up in my tap water plus whatever the fish produce. But perhaps the nitrates in the tap water are not a form that is useful or easily absorbed by the plants meaning that they are only really getting nitrogen from the fish cycle - which may not be enough. Is this something that's possible? Perhaps I should actually be adding some Nitrogen?

 

[dw1305]

Hi all,

I noticed that the upper leaves on one of the newer plants (Tropica - Hygrophila 'Siamensis 53B'), which have started to show some of the same dark green blotching, are turning pale and translucent. My impression has been that this is the expected 'transition' from an air reared plant to underwater growth. It's been in the tank for a few weeks now and the top leaves have just about reached the surface.

It might be a light intensity effect now it has surfaced, or it might be the start of iron deficiency. This is iron deficiency in Hygrophila corymbosa, (photo by @sciencefiction) <"EI dosing......"> .

it was reading around 395, then at about 7pm it was reading 410; so still really just hovering around the same sort of reading as yesterday

If the water was warmer at 19:00? That may account for the difference.

Thinking on my experiences with growing tomatoes and chillis using hydroponics, the Ph is very important in terms of allowing proper uptake of nutrients. If the Ph of the nutrient solution is too high many essential nutrients are 'locked out' and cannot be absorbed by the plant leading to deficiencies even if the nutrient is abundant in the solution. I seem to remember something around Ph 5.6-6 was a sweet spot to be targeted. Does the same issue not occur in planted aquariums?

Yes, it does. All plants (even things like Cacti) can only take up nutrients as ions from solution.

I've seen reference to people noticing that their plants respond well to a low KH - but perhaps what's really going on there is that the low KH leads to a lower Ph (when the CO2 is on) and that's what's actually causing the plants to take up nutrients and respond well?

It is back to the <"Donald Rumsfeld's "unknown unknowns">, but it is certainly feasible and my suspicion would be, at least part of, the answer.

You can see the process (of a solid becoming ions) occurring in snails in a high tech, where you get <"shell attrition"> during the "CO2 on, lower pH" period.

Now the opinions on what levels of nitrates are toxic (or even unpleasant) for fish and shrimp seem to be mixed, as are opinions on whether nitrates from added nutrients are really the same as nitrates from the bacteria based filter cycle.

We have a lot of <"threads about this">, the problem is that it is really only aquascapers who add the nitrate (NO3-) ion from a salt (usually KNO3), rather than it being the "smoking gun" of previously high levels of the, definitely toxic, ammonia (NH3/NH4+) and nitrite (NO2-).

But perhaps the nitrates in the tap water are not a form that is useful or easily absorbed by the plants meaning that they are only really getting nitrogen from the fish cycle - which may not be enough. Is this something that's possible?

No you are fine, plants can take up all forms of fixed nitrogen (NH3/NH4+, NO2- & NO3-) and every NO3- ion is the same as every other NO3- ion.

cheers Darrel
.

 

[Witcher]

or it might be the start of iron deficiency. This is iron deficiency in Hygrophila corymbosa,

Most possibly Fe, but it also might be N/Mg deficiency which are the ingredients of the chlorophyll or it might be release of N by plant caused by photorespiration.

 

[dw1305]

Hi all,

but it also might be N/Mg deficiency which are the ingredients of the chlorophyll

It was just mention of <"new leaves"> that made me wonder <"about iron (Fe)">.

As you say there are other causes of chlorosis (like <"deficiencies of nitrogen (N)"> and <"magnesium (Mg)">), but these are nutrients that are mobile within the plant and they effect older leaves first.

If you look at the Hygrophila top leaves on the left of @sciencefiction's picture that is definitely an iron deficiency, but the colour of the plant suggests that there maybe other issues as well. The pattern of dark veins and pale leaf tissue in older leaves often indicates <"magnesium issues"> below.

Iron isn't mobile within the plant and it is only new leaf tissue that is green again. This is my new favourite "diagnostic" photo .

Hears a pic of my Fe deficiency

cheers Darrel

 

[Witcher]

but the colour of the plant suggests that there maybe other issues as well.

Hey @dw1305 , yes, that what I was thinking of, generally when I see yellow or very bright leaves leaves I think of Fe/N/Mg (depending on the leaves age).

BTW I must admit that Fe deficiency on that Pogostemon looks really cool, I'd be tempted to intentionally cause that for such a nice look.