Javafern discolouration

brendonjw · Dec 1, 2021

Hi All,

My Java ferns are starting to melt. The first one has gone and produced a heap of little ones but i'd like to try and save my other one. The leaves are starting to have dark spots like below on them. Any ideas? Yes there is algae in the tank on another piece of driftwood but i can't see any on the piece that this Java fern is on. I wasn't doing any ferts previously but have started to use api leaf zone incase it was low on anything.

Cheers

WhistlingBadger · Dec 1, 2021

If it's getting big black spots, check your nitrates. I have found that java fern, while otherwise indestructible, doesn't deal well with high nitrates. Before I started using test kits, I used Java fern as a canary in a coal mine. If it started getting black spots, I knew it was time to clean the filter, reduce feeding, and do a big water change.

itiwhetu · Dec 1, 2021

What is the pH of your tank, please.

brendonjw · Dec 2, 2021

My nitrates are always very low 0-5, the tank is very lightly stocked. I havent checked the pH recently, i'll do that when i get home.

Byron · Dec 2, 2021

This most likely has something to do with the light. There is a lot of algae on all the plants in the photo, and from the brightness I am assuming you do not have floating plants to shade the Java Fern. This is a low light plant. I don't see any nitrogen-related black spots on the plant in the photo so I would doubt that being the issue.

API Leaf Zone is not likely to help; it is potassium and iron. Excess iron can cause algae, not to mention it can kill plants, I had it happen when I foolishly listened to someone suggesting iron fertilizer, and it did it twice. Get a comprehensive supple4ment, Seachem's Flourish Comprehensive Supplement, or Brightwell Aquatics FlorinMulti, or (this one I think is only available in the UK but just in case...) TNC Lite.

Any data on the light (spectrum, intensity, duration)? Floating plants will benefit all of this too.

brendonjw · Dec 2, 2021

Byron said:
This most likely has something to do with the light. There is a lot of algae on all the plants in the photo, and from the brightness I am assuming you do not have floating plants to shade the Java Fern. This is a low light plant. I don't see any nitrogen-related black spots on the plant in the photo so I would doubt that being the issue.

API Leaf Zone is not likely to help; it is potassium and iron. Excess iron can cause algae, not to mention it can kill plants, I had it happen when I foolishly listened to someone suggesting iron fertilizer, and it did it twice. Get a comprehensive supple4ment, Seachem's Flourish Comprehensive Supplement, or Brightwell Aquatics FlorinMulti, or (this one I think is only available in the UK but just in case...) TNC Lite.

Any data on the light (spectrum, intensity, duration)? Floating plants will benefit all of this too.

Thanks for that, I have https://aquaone.com.au/2015-04-16-04-47-04/reflectors-2/item/3998-59015 for lighting and leave it on for 11 hours a day. I'll try reducing the hours, how long to do recommend? I recently got some floating plants (water wisteria) which are starting to spread. I'll get a full photo of the tank so you can see.

Byron · Dec 2, 2021

There seem to9 be more than one type of this light, which one do you have? There is Sunlight, Tropical, Plant and Marine.

As for the duration, 11 hours is a lot, but it is also the intensity that matters; these two are not complimentary, by which I mean too bright a light is still too bright whether on for 6 hours or 12 hours, and in reverse if the light is not bright enough for the plants, leaving it on longer does not compensate. My tanks are on for 7 hours, as over a period of 2-3 years I worked it out that this was the most I could have given my light, plants, and daylight. There is (they say on the site) a way to adjust the intensity (brightness), which might help.

The photo will help, thanks, I'll wait for it.

brendonjw · Dec 3, 2021

Byron said:
There seem to9 be more than one type of this light, which one do you have? There is Sunlight, Tropical, Plant and Marine.

As for the duration, 11 hours is a lot, but it is also the intensity that matters; these two are not complimentary, by which I mean too bright a light is still too bright whether on for 6 hours or 12 hours, and in reverse if the light is not bright enough for the plants, leaving it on longer does not compensate. My tanks are on for 7 hours, as over a period of 2-3 years I worked it out that this was the most I could have given my light, plants, and daylight. There is (they say on the site) a way to adjust the intensity (brightness), which might help.

The photo will help, thanks, I'll wait for it.

I have the Sunlight one.
The photos are of the 3 different options for intensity for the light (and one without the light on for comparison.)

brendonjw · Dec 4, 2021

itiwhetu said:
What is the pH of your tank, please.

PH is about 7.8

itiwhetu · Dec 4, 2021

brendonjw said:
PH is about 7.8

This plant likes soft acid water. Your pH is too high for it to do well.

Byron · Dec 4, 2021

brendonjw said:
I have the Sunlight one.
The photos are of the 3 different options for intensity for the light (and one without the light on for comparison.)

The Kelvin data for those lights in the link are confusing. The sunlight should be OKJ though...but there is a lot of diffused daylight in the room, evident especially in the last photo. This will contribute to algae, I used to see this every summer until I realized what it was and covered the windows completely (easy to do in a dedicated fish room, not so easy in living quarters). Reducing the tank lighting should help this.

There is no issue with pH:

Water parameters

Moderately soft to hard, slightly acidic to basic (pH 6-8) water, temperature 18-30C/65-86F. Can tolerate slightly brackish conditions.

itiwhetu · Dec 4, 2021

Here is the cultivation information for this plant out of "The encyclopedia of water plants". I still believe pH is your problem with this plant

brendonjw · Dec 5, 2021

Thanks for all the advise, yes the tank is in the living room so i dont think the wife would be too happy about blocking all the windows off.

Somehow i have managed to keep snails out of the tank so i'm think of trying some ramshorn to see if they will help me keep on top of the algae on the plants.

Apart from the PH suggestion im still not sure what could be causing those spots. I'm going to take one of the smaller ones that has started growing and put in my spare quarantine tanks in a darker room and see how it goes.

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