# Algae and poor health of floating plants



## MissATV (6 Oct 2020)

Hello everyone,

Please may I ask for you advice regarding the health of my Pistia Stratiotes. I have it in a tank which has been set a few months ago, up until 2-3 weeks ago it has been growing well in the sense of shooting new plants and covering my water surface. The plants have been green but recently they have started to become yellow/brownish and some leaves have yellowed completely and have holes in them and the growing has slowed down a lot recently.  It looks like an algae to me, but I have no idea what could have caused it as until now it never appeared. It seems to mainly affect the Pistia and it was on one leaf of the Anubias but I scraped it off. 

The rest of the plants in the tank are doing fine, the light I have is the one which came with the tank an LED of 8w I believe and there is a smaller one of 2W which I added as a evening light. Both are on together for 8 hours and then I switch the main one on and leave 3 hours of the 2W before bedtime.  

The temperature is set to 25 C, once a week I dose some Tropica specialized fertilizer in very small quantity. 30% water change done weekly with water from tap, which is quite high in nitrates (according to API test) and GH is 12 and KH is 16, Ph is 7.8 

I have attached some photos, I will appreciate any insight or advice on what's happening with the floater and if I can help it in any way.


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## dw1305 (6 Oct 2020)

Hi all,
Nice tank and male _Apistogramma cacatuoides_. I like your <"structural leaf litter">.

The brown looks likely to be diatoms. They may have become more obvious because root growth has slackened.

The _Pistia_  rosettes don't look too bad at all.

It might be  a light effect, if the tank receives some ambient light? It may just be the decline in light level <"as the seasons change">. If the tank is getting the same amount of light, it may be that there are less nutrients in your tap water now that you have <"much greater dilution from heavier "> rainfall.

Assuming it isn't light, I'd just try a bit more fertiliser.

cheers Darrel


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## sparkyweasel (6 Oct 2020)

It looks to me as if the ' yellow/brownish ' leaves are submerged. They don't take well to being under the surface. They may have got pushed under as the _Pistia _grew in size and increased in numbers. I would trim off those leaves, and remove few of the plants to let the others spread out.


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## Karmicnull (6 Oct 2020)

Yeah my Pistia does the same thing - the new growth forces the older leaves into the water where they sulk and die off. But all your new leaves look very happy.


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## rebel (7 Oct 2020)

Suggest adding Potassium phosphate to this tank and observe for 4 weeks. I am suspicious of K or PO4 deficiency when I look at some of the leaves of the Java as well.

Ideally change nothing else; FOR SCIENCE!


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## MissATV (8 Oct 2020)

Thank you all for the replies, I really appreciate it.

In terms of light, nothing has changed the blinds are mostly down in this room as I try to avoid any daylight coming through although I do have my partner leaving them up for a few hours when he works...I did notice the "brownish" starting on the side where the light was entering the room.

I am looking at them today and as we stand I feel they look at lot worse, even though the cover of the surface has been reduced (I did see the submerged leaves dying so I took a few out) it still looks like they are getting worse actually.  I will try to dose maybe twice a week tropica specialized. I also have Kalium-Potassium from easylife and liquid co2 from easy life which I could add if needed?


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## tyler138 (14 Oct 2020)

My frogbit goes a bit brown/yellow at times, and I think its due to getting pushed underwater, by the filter or new growth. 

I also get small holes, which I think is from light going through the condensation droplets on the lid.


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## dw1305 (14 Oct 2020)

Hi all, 





MissATV said:


> it still looks like they are getting worse actually. I will try to dose maybe twice a week tropica specialized. I also have Kalium-Potassium from easylife and liquid co2


The liquid carbon won't make any difference , but you could definitely try a few more nutrients, they still look pretty healthy. 





MissATV said:


> I did see the submerged leaves dying so I took a few out


Just pinch the yellowing leaves off. Mine are also shrinking at the moment, but in my case I think it is a light issue because the tanks get some ambient light. 





tyler138 said:


> My frogbit goes a bit brown/yellow at times, and I think its due to getting pushed underwater, by the filter or new growth.I also get small holes, which I think is from light going through the condensation droplets on the lid.


Can we have a picture?  I use Amazon Frogbit (_Limnobium laevigatum_) for the <"Duckweed Index">.

Have a look at <"micronutrient....">,  <"Duckweed Index says....."> and <"Frogbit taken a turn.....">.

cheers Darrel


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## MissATV (14 Oct 2020)

Thank you so much Darrel, 

I added a few more ferts and it seems like they are slowly picking up a bit. Like you mentioned earlier it could be the season, in a nano 21L which I have with corys and shrimps they seem to be thriving so I think there is more "food" for them being more nitrates in the tank for them?


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## dw1305 (15 Oct 2020)

Hi all,





MissATV said:


> I added a few more ferts and it seems like they are slowly picking up a bit


That sounds promising. 





MissATV said:


> being more nitrates in the tank for them?


It is likely to be NO3, purely because the elements that plants need most of are carbon (C), nitrogen (N), potassium (K) and phosphorus (P). You've covered carbon because you have a floating plant, and out of N: P: K: plants <"need a lot more N and K than they do P">.

Nutrient deficiencies are always to some degree guess-work, but you can improve your guess if you look at <"compound solubility">, <"nutrient availability & pH"> and whether a nutrient is <"mobile within the plant">.  

cheers Darrel


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## rebel (15 Oct 2020)

MissATV said:


> liquid co2 from easy life which I could add if needed?


Don't increase this. 

I regularly concur with @dw1305 so will do so now.... 



dw1305 said:


> Nutrient deficiencies are always to some degree guess-work


Educated guesses of course.


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## dw1305 (27 Oct 2020)

Hi all, 
@MissATV, how are things now?

cheers Darrel


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## MissATV (30 Oct 2020)

dw1305 said:


> Hi all,
> @MissATV, how are things now?
> 
> cheers Darrel



Quite bad I'm afraid. Majority of the floaters have died. They improved at first and then they suddenly stopped a growing new shoots completely. Their roots die too, I have no idea why, they become hair-like looking and then I see them breaking off and gone. I upped the water changes to 50-60% weekly in case it's a nutrient deficiency. But I am starting to suspect it could be too much water movement, I moved the internal filter lower so it creates less ripples but still no success. what's weird is the same plants are in a separate blackwater tank of 21l which is overstocked but there they grow fine and in that one I did not dose anything extra.


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## dw1305 (30 Oct 2020)

Hi all, 


MissATV said:


> Majority of the floaters have died.


I'm sorry to hear that, I'm not sure what to suggest. 

Quick question: how long is your photo period? and ca you adjust the brightness of the light?

cheers Darrel


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## MissATV (30 Oct 2020)

Photo period is from 9am-5pm 10w (one bulb 8w and a separate one 2w) and then from 5pm-9pm I leave just the 2w on as a "evening light". I can adjust them by switching any of them off


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## dw1305 (30 Oct 2020)

Hi all, 


MissATV said:


> Photo period is from 9am-5pm 10w (one bulb 8w and a separate one 2w) and then from 5pm-9pm I leave just the 2w on as a "evening light".


I'd try the full 12 hours (9:00 - 21:00) with 10W and see what happens. 

cheers Darrel


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