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15 Posts
Discussion Starter · #1 ·
Hi all,

I have a large open top tank (200X70X60 cm) That has been running for roughly a year. As visible on the picture below, my scape contains a large "wall", which holds a very large amount of ADA Malay soil behind it as well as some power sand on the bottom. My goal has always been to use less demanding epiphytes and crypts under water, create a lush overgrowth above water with march plants that grow in the ADA soil in roughly 10 CM of water and have access to unlimited CO2 above the surface. I do not use CO2 in the water column, but started dosing FloraGrow liquid fertilizer as per the instructions on the packaging a few months ago on a daily basis.

However, after a year of running this tank I am still struggling to grow my emerged section well, and my problems usually go like this:

I plant something (e.g. an Amazon Sword), it takes of fast, and after shooting out great growth an leaves for two months, the plants start melting and showing serious signs of deficiency. By now my amazon swords are fully gone, but even my dwarf lilly (which was doing great after I increased lights and started dosing liquid fertilizers and at some point had 12-15 large leaves at the surface) started breaking down completely (See attached picture for deficient/melting Lily pads). On top of all of this, my Bolbitis that was growing on wood at various places in the aquarium has all but disappeared, and my peace lily's are nothing more than a few sad leaves.. Java ferns are doing Okisch with some leaves showing some yellow while others look healthy. My Hydrocotyle tripartita however seems to be doing great and has done a good job colonizing my "emerged island".

I was hoping that the daily dosing of fertilizer would solve my problems (note that I have also been feeding root feeders like sword and lilly with root tabs), but every time things seem to be getting better some other plant starts melting again :)

I would truly appreciate some input from folks that have had similar experiences or can see from the affected leaves what the issue might be (pictures below). Thanks a ton in advance!!!



15 Posts
Hi @Ramon D,

Do you have any water parameters you could share? pH. dKH, dGH, nitrates (ppm of NO3)

What exactly are you dosing?

How much?

How often?
I will make sure to get my water tested properly this weekend and report back with detailed values.

My reading comes back like this:

NO3 10-25 mg/L
NO2 0 mg/L

dGH >7
DT 7-14
TH 14

KH=TAC 3-6
pH 6.8

I can get my water tested this weekend at my LFS for better accuracy but hope that helps in determination. I do water changes once every one to two weeks. Given the large volume of the aquarium I do roughly 10-20% changes.

Hope that helps.


Generally the process gows as follows:

1. First, growth seems to be great and plants grow very well, especially emergent (Peace Lily, Dwarf Lily, Amazon Sword).

2. Second, old leaves start to show signs of decay. This looks slightly different for different plants, but in general includes either leave tips turning black or brown (especially for emergent growth) and then holes/decays in the leaves, or leaves turning yellow/opaque with holes forming afterwards (under water). In this stage, new leaves are still produced frequently and initially look healthy.

3. Finally, old leaves die off faster than new leaves replace them, or new leaves start to die/decay before maturing.

I am assuming that Nitrates and CO2 are not the primary deficiency for the following reason:

1. Nitrate reading is 10-25 ppm.
2. Emergent growth seems to be struggling more than underwater growth, which should theoretically rule out CO2 as the main deficiency.

I am not sure what the reference to black dots connects with, but the black dots on the anubias are green spot algae, and the anubias are doing quite well :smile2: The same goes for the hydrocotyle tripartita as seen on the pictures. Also my crypts are doing fine.

The plants that are most effected are in order of severity:

1. Amazon sword (completely died)
2. Dwarf Lily - Did great but I am afraid it is going the same way the Sword did.
3. Bolbitis - I had great growth and they are now almost gone
4. Java fern - seems to be doing quite OK, but more yellowing leaves than before...

I have used different brands of root tabs and used them once every 1-2 months for heavy root feeders like the lilly and Swords, as well as for the crypts.
I will look up the exact specs of the FloraGrow Pro Special Fertilizer that I am dosing, but I generally dose the recommended dosage of 10ml per 50L.

Hope this helps, and thanks for your help!

Based on the details provided in my previous posts, and the amazing source providing by @Zapin on this forum, I have narrowed down my deficiency to one out of two possible nutrients. It must be either (K) Potassium, or (P) Phosphorous.

The lesions on my Lily leaves, as well as pinholes found in my java fern and hygrophila pinnatifida (on closer inspection I found smaller pinholes in those leaves), all seem consistent with a deficiency in (K). However, the decay for emergent leaves (as can be seen on the pictures of the Peace Lily leaves) seems to be consistent with the (P) deficiency that describes browning starting from the edges and tips of the leaves.

If anybody has a trained eye and can give me an expert opinion between those candidates, that would be very much appreciated!

So now I am in a total state of confusion:

I bought a potassium test kit, and my (K) measured really high at more than 20 mg/L.... on the highest end of the test. Not really sure what else I could look at.

My Nitrates measured at 10-25ppm
and my Phosphorous also measured decent (I forgot the exact reading.

Any ideas?

15 Posts
Discussion Starter · #6 ·

Thank you so much for your in-depth analysis, the time you spent to help me and for your valuable insights. I am truly grateful for your help! I will make sure to do another Phosphorus test myself tomorrow and update this thread(I got the Phosphorus tested at the LFS during the weekend and forgot the exact value), and follow your advise as a next step. I will report back in two weeks with the results! Thanks again!!

15 Posts
Discussion Starter · #7 ·

Sorry for the delayed update on my end. I have been traveling a lot lately, and I wanted to make sure I had conclusive feedback before updating you. While it took a little longer than expected, it sure looks like the magnesium is working to restore plant health. I now have 12 healthy leaves again on my dwarf lily, and other plants have been showing significant improvement too.

I will try to post some new pictures this weekend, but wanted to already take some time to profoundly thank you again for your help and efforts to help me diagnose the issue!

Best, Ramon
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