Plants doing really poorly. Why?

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BettaGamma

Aquarium Advice Newbie
Joined
Feb 8, 2021
Messages
8
Location
Berkeley, CA
Hi all,

I have a lightly-moderately planted tank I set up back in November--my first tank since I got tired of the hobby way back in middle school, lol. The plants started out doing fairly well but now look, quite frankly, terrible. Hoping someone more experienced can help me to diagnose why that may be. Some stats and params on the tank:

10 gallon
Finnex Planted+ 24/7 HLC, runs 6-9 hours a day (I'll explain what that means below)
*White led 100%, blue and reds 10%
Running Seachem Tidal 35 and air pump + sponge filter
Ammonia/Nitrite/Nitrate: 0/0/0-5
pH/temp: right around 8/78 F
Dose 1mL API CO2 booster every day, 1 mL Flourish Comprehensive 2x per week
Used 6 seachem root tabs back in November, have since supplemented maybe 3 or 4
Seachem flourite black sand substrate (~2.5 in. all around)

Been doing 40-50% wc every week in an effort to suck algae/debris out of the tank, but thinking I will start 1x every 2 weeks and in lower volumes to build some nitrate up as I suspect a possible nitrogen deficiency

Plants
Crypt wendtii green
Crypt parva
Crypt lutea
S repens
Dwarf Sag
Amazon Sword Compacta

Phew! All that out of the way, some of the leaves on most of the plants (save the sword) have brownish patches on them like they're decaying. The s repens looks especially terrible--the old leaves are almost completely brown and the new green ones at the top don't look fantastic either. Additionally some of the new leaves from the sword (I recently pruned probably half of its leaves since they looked so unhealthy) are coming in twisted--possible Ca deficiency??.

Hard for me to tell if this is all due to a nutrient deficiency or if they're infested with algae/diatoms. I should mention that I had some pretty bad algae issues towards the beginning despite being conservative with the lighting to begin with, including thick green slime coating a lot of the leaves and some cyanobacteria for a time. Both have disappeared since I've been dosing liquid co2 but I have pretty significant green algae on my glass still (still trying to figure out the right photoperiod/intensity) so I wonder if it's algae on the leaves blocking out light and creating the issue. However, I've tried gently scraping off the leaves like has worked in the past but nothing readily comes off.

The finnex light is a little weird in that you program in 3 hour slots, but the light gradually ramps up from darkness to your first light setting (and vice versa) over the course of 3 hours as well. I.e. I have the light set to be on for 12-3 and 3-6 (solid 6 hours), but the light gradually comes on (I assume linearly) from 9-12, and gradually off from 6-9. I consider this 9 hours in total (since I figure 9-12 and 6-9 are equivalent to 1.5 hours roughly). I keep the white lights at 100% and the reds and blues at 10% whenever it's on. I'm not sure if the plants look as bad as they do because of not enough light, or if the algae is harming the plants and I need to tone the light down. Although I still suspect the true bottleneck here is ferts.

Another thought: would it be advisable to buy some more plants that are fast growers to help choke out the algae, since mine are generally slow root feeders? Perhaps some valls and/or a floating plant? I'd like a more densely planted tank regardless but perhaps this would help.



TL;DR, my plants are doing pretty bad (i.e. brown patches on old leaves, gnarled growth on amazon sword) despite pristine water, consistent ferts, and what I think is pretty moderate lighting. Do I need to cut down on/increase lighting, address some nutrient deficiencies, buy some faster growing plants, or some combination of the 3?

Sorry to be so long winded. I will post photos of each of the plants in the morning when the lights come on again.

Thanks for your assistance, in advance.
 
Taking all of the information in to account it sounds like your lighting is too high.

When purchased, most plants have been grown above water so they have access to aerial carbon dioxide (co2) and plants are very good at storing co2 and oxygen.

When you place them under water they must alter their leaves from waxy cuticles that can repel water and predators to thinner leaves that can move gases in and out.

Initially their stores of energy that were obtained when grown above water are used and everything appear to be going well. Once those reserves run down the plants start to struggle.

When a photon (light energy) hits a leaf it catalyses a photosynthetic reaction and in order to complete the reaction thoroughly, there needs to be access to co2. There is obviously co2 available in aquariums that do not supplement but it is at a much lower value.

If your light emits a lot of photons over a given area every second you are forcing the plant to carry out reactions that it doesn’t have the resources to complete efficiently and they starve. Other than supplementing co2 via injection, the easiest way to alleviate this is by lowering the light intensity.

Algae in young set ups such as yours is also inevitable. It takes a good while for things to settle down. When plants starve or discard leaves during transition, they break down in to the water column which can strain oxygen levels and stimulate algae. Adding fertilisers then exacerbates the issue.

Liquid carbon fertilisers are not co2. They are an algaecide that cleans the leaf surfaces of periphyton which enables better gas transfer.

You can easily rule out nutrient deficiencies by adding a floating plant to your tank. Because they have access to lots of photons and atmospheric levels of co2 they require lots of nutrients. If this rapid growth of a floating plant occurs and remains healthy then nutrient deficiencies can be ruled out. This is known as the Duckweed Index coined by a member of the UK Aquatic Plant Society and is used by many hobbyists there today.

First lets try these two simple changes before we get in to nutrients. Remember things don’t happen over night so patience is key here.
 
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Thanks for the quick reply,

Duckweed index is brilliant, I would've never thought to do that. It's difficult for me to get live plants here (I have to order online) but I will try to get my hands on some asap.

In the meantime, seems like you're suggesting reducing the lighting. Would you suggest that I cut the intensity or the photoperiod, and by how much?

Also, do the photos tell you anything about what may be going on, or do they just confirm your suspicions about the lighting?
 
Thanks for the quick reply,

Duckweed index is brilliant, I would've never thought to do that. It's difficult for me to get live plants here (I have to order online) but I will try to get my hands on some asap.

In the meantime, seems like you're suggesting reducing the lighting. Would you suggest that I cut the intensity or the photoperiod, and by how much?

Also, do the photos tell you anything about what may be going on, or do they just confirm your suspicions about the lighting?


You’re welcome.

Note that most people think that Duckweed is an incessant nuisance. It will become a chore to keep on top of but it can be kept in a bucket with some tank water and used as and when needed.

It really is a cool method for checking ferts though I think the person who came up with the concept has revised the plant choice to amazon frogbit as it grows in hard and soft water and is ‘persists in low nutrient situations’

Always the intensity. The units of which are described as micro mols of photons per square meter per second (umol/m2/sec). If you lower this number you have less photons and less requirement for co2. Try cutting it by half. The plants you have don’t particularly need high light intensity. I have the same plants under a canopy of salvinia and tiger Lilly’s in tannin stained water with naturally low lighting intensity and they grow fine though slow but that is down to liebigs law of the minimum and nothing to do with lighting.

You can’t really identify deficiencies very well by looking at the plants unless they are pale, in which case it is an obvious nutrient deficiency of either iron, nitrogen, potassium or magnesium. The newest (central) amazon sword leaf looks better. You should always focus on new growth never the old growth unless you are looking for a greening effect.

I do see some brown algae on the glass which suggests to me that your tank isn’t biologically stable. This could be due to the instability large and frequent water changes can bring, possible chlorine/chloramine issues, constant uprooting and disturbing of plant roots, low oxygen levels and/or the use of glutaradehyde (liquid co2).

I’ve had and seen a lot worse and you definitely need more plants and a bit more time with more tank stability.
 
You’re welcome.

Note that most people think that Duckweed is an incessant nuisance. It will become a chore to keep on top of but it can be kept in a bucket with some tank water and used as and when needed.

It really is a cool method for checking ferts though I think the person who came up with the concept has revised the plant choice to amazon frogbit as it grows in hard and soft water and is ‘persists in low nutrient situations’

Always the intensity. The units of which are described as micro mols of photons per square meter per second (umol/m2/sec). If you lower this number you have less photons and less requirement for co2. Try cutting it by half. The plants you have don’t particularly need high light intensity. I have the same plants under a canopy of salvinia and tiger Lilly’s in tannin stained water with naturally low lighting intensity and they grow fine though slow but that is down to liebigs law of the minimum and nothing to do with lighting.

You can’t really identify deficiencies very well by looking at the plants unless they are pale, in which case it is an obvious nutrient deficiency of either iron, nitrogen, potassium or magnesium. The newest (central) amazon sword leaf looks better. You should always focus on new growth never the old growth unless you are looking for a greening effect.

I do see some brown algae on the glass which suggests to me that your tank isn’t biologically stable. This could be due to the instability large and frequent water changes can bring, possible chlorine/chloramine issues, constant uprooting and disturbing of plant roots, low oxygen levels and/or the use of glutaradehyde (liquid co2).

I’ve had and seen a lot worse and you definitely need more plants and a bit more time with more tank stability.

Got it, I'll probably look at getting frogbit instead if you say it will serve the same purpose, and I'll go ahead and start incrementally reducing the light.

Just now I was looking at what the cost of running CO2 on the tank would be hypothetically, and while I don't think I can afford a pressurized system (I'm a broke college student pinching his pennies!!), would DIY CO2 (e.g. using yeast or NaHCO3 + citric acid) be worth considering in your opinion/experience?

You're obviously well versed on the science behind all this, would you have any reading you could recommend to someone like me or is this all just from experience?
 
Got it, I'll probably look at getting frogbit instead if you say it will serve the same purpose, and I'll go ahead and start incrementally reducing the light.



Just now I was looking at what the cost of running CO2 on the tank would be hypothetically, and while I don't think I can afford a pressurized system (I'm a broke college student pinching his pennies!!), would DIY CO2 (e.g. using yeast or NaHCO3 + citric acid) be worth considering in your opinion/experience?



You're obviously well versed on the science behind all this, would you have any reading you could recommend to someone like me or is this all just from experience?


By all means you can experiment with the yeast or citric acid methods although someone else who has tried it before will need to guide you if you decide to go down that route as a ended up going straight to pressurised cylinders.

Supplemental Co2 will always benefit submerged plants but it is by no means a necessity. My point was to illustrate why plants react poorly to being placed under water. And why high light intensities and no co2 can lead to issues.

Most of the plants we keep are semi aquatic due to seasonal flooding. They can and do change their leaves and their new leaves will have a higher affinity to catch co2 so first you should rule out a nutrient issue. Plants like fish and microbes enjoy stability and the plants you have can do just fine with the levels you have. Also, because you have a sponge filter you are adding oxygen via the bubbles breaking the surface. Higher oxygen means faster breakdown of wastes = more co2 :)

I don’t use co2 anymore. I keep shrimp and snails and they do not appreciate it.

I get most of my information from what I have read and seen over the years on forums. I also mix with great resources including scientists and shop owners. Of course Diana Walstads ‘Ecology of the planted aquarium’ is a staple and will set you well on your way but I do have a lot of experience through actual non scientific testing. At the moment I’m running a system that is so alien to many modern hobbyists and I’m having a blast.

You really do need to have an open mind in this hobby and understand that there lots of ‘shades of grey’ where many methods can work though not always for the reasons you believe :)

You need to find out what you enjoy the most about the aquarium because a lot of the time, what we do to appease a vast array plants from different parts of the world doesn’t always bode well for the fauna.
 
By all means you can experiment with the yeast or citric acid methods although someone else who has tried it before will need to guide you if you decide to go down that route as a ended up going straight to pressurised cylinders.

Supplemental Co2 will always benefit submerged plants but it is by no means a necessity. My point was to illustrate why plants react poorly to being placed under water. And why high light intensities and no co2 can lead to issues.

Most of the plants we keep are semi aquatic due to seasonal flooding. They can and do change their leaves and their new leaves will have a higher affinity to catch co2 so first you should rule out a nutrient issue. Plants like fish and microbes enjoy stability and the plants you have can do just fine with the levels you have. Also, because you have a sponge filter you are adding oxygen via the bubbles breaking the surface. Higher oxygen means faster breakdown of wastes = more co2 :)

I don’t use co2 anymore. I keep shrimp and snails and they do not appreciate it.

I get most of my information from what I have read and seen over the years on forums. I also mix with great resources including scientists and shop owners. Of course Diana Walstads ‘Ecology of the planted aquarium’ is a staple and will set you well on your way but I do have a lot of experience through actual non scientific testing. At the moment I’m running a system that is so alien to many modern hobbyists and I’m having a blast.

You really do need to have an open mind in this hobby and understand that there lots of ‘shades of grey’ where many methods can work though not always for the reasons you believe :)

You need to find out what you enjoy the most about the aquarium because a lot of the time, what we do to appease a vast array plants from different parts of the world doesn’t always bode well for the fauna.

A lot of great points here. And that's not the first time I've been recommended Walstad's book, I'll have to give that a readthrough (or a few).

Upon poking around a little further I've realized that many, if not all, of the brown spots on the leaves ARE actually some sort of algae that does scrape off, after a lot of rubbing with my fingernail. I was fearful of using too much force and damaging the leaves the first time around so I hadn't realized. I don't have the time to sit there and scrape algae off each individual leaf (at least not right now), but would cutting the light to half still be of benefit here? Is there any sense in manually removing all that algae or is it just a question of tweaking the lighting?
 
A lot of great points here. And that's not the first time I've been recommended Walstad's book, I'll have to give that a readthrough (or a few).



Upon poking around a little further I've realized that many, if not all, of the brown spots on the leaves ARE actually some sort of algae that does scrape off, after a lot of rubbing with my fingernail. I was fearful of using too much force and damaging the leaves the first time around so I hadn't realized. I don't have the time to sit there and scrape algae off each individual leaf (at least not right now), but would cutting the light to half still be of benefit here? Is there any sense in manually removing all that algae or is it just a question of tweaking the lighting?


In my experience brown algae goes away with time which suggests a stability issue. Tank stability goes way beyond the nitrogen cycle. Especially in a planted tank.

As for the light, that is for you to play around with. Try things and see. It will make you a better aquarist. Keep a journal and don’t change too many things at once. Keep us updated.
 
Just a few updates if anyone wants to chime in/recommend anything I should do differently

I've since reduced the light intensity to 50% and have noticed considerably less algae on the glass, so I will likely stick with that for the time being.

I ordered some duckweed, corkscrew vals, and water wisteria with the hopes that they'll grow fast and starve the algae on the plant leaves of nutrients. Arrived this weekend in pretty rough shape and I didn't have the presence of mind nor patience to complain/try to get new ones, and the vals have since melted back a ton. I'm hoping they will bounce back but many of the plants had tiny root structures to begin with so I'm not especially hopeful... time will tell.

I've also come to realize that the "algae" infesting the plants is probably cyanobacteria, or at least much of it is. Had trouble id-ing it since it looks much darker and less "slimy" than any images I've found, but the fact that it comes off in sheets and I've historically noticed a weird earthy scent from the tank, that's what I believe it to be. Decided to dose erythromycin today and I hope that provides the opening for the new fast growing plants to take off and get a foothold rather than the BGA
 
In all honesty I can say at this point from both experience and observational standpoints that this is very typical of an aquarium that is still maturing.

I can’t say or do not know why but diatoms and Cyanobacteria along with other types of algae are sort of like a sign that our aquarium is ‘going through the motions’

The Vals will likely grow back.

One thing I have found quite helpful is making sure the tank water has as much oxygen as possible. The theory is that higher oxygen levels will accelerate the microbial breakdown of organic wastes. Once you have little organic waste making for a ‘cleaner tank’

Aeration, feeding less and removing organic wastes regularly will help with this.
 
Removing algae off the aquarium rock only needs a straightforward process. But you will need to remove other parts during the cleaning, such as the decorations and the plants. You also need to remove it slowly not to stress the fish.
You can get a new toothbrush and scrub the rocks thoroughly to remove the algae. You can also create a 5% bleach and 95% warm water bleach solution and soak the rocks again. Use the toothbrush to scrub the rocks again.
 
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Is this true for all snails or are some ok with Co2?



I haven’t kept all types so I can’t say. Also I have no idea exactly how much co2 I was using because the drop checker is not an accurate tool for measuring co2. It very may well be possible to keep the co2 low enough to not cause issues yet high enough to stimulate plant growth.

I read an article once that said that if you have good surface agitation (to ‘gas off’ co2) you can turn the co2 up to compensate and therefore achieve a higher co2 equilibrium and create a safety ‘cap’. I think this would be a good practice.
 
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