# Black edge on leaves



## Zapins (Jan 7, 2006)

Is this on other plants as well?

Looks like an algae. See if the leaf itself is damaged or if it is something on the leaf.


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## JJVanier (Feb 4, 2014)

Looks like the start of some sort of thread/fuzz algae.

If you can confirm its algae there are some options to deal with it including, cutting your light duration to 4-6 hours, adding fast growing stem plants or floating plants to compete with the algae, increasing water change schedule, trimming the affected areas.

Dosing with excel, or spot treating with excel or hydrogen peroxide 3% are options as well but not necessary if you can nip it in the bud.


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## dmagerl (Feb 2, 2010)

I get this on my plants too. Its not BBA. It never develops into the typical bushy BBA form, though it is related to BBA. Its black and it turns pink when dosed with Excel. 

I call it black dust algae but thats just my name for it. I have no idea what it really is.

It mostly confines itself to the edges of plants and is an indication the plants arent growing too well. 

I've managed to slow mine down but havent got rid of it. I just have to do constant pruning to continually prune off the older leaves.


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## phxhot04 (Dec 19, 2013)

dmagerl said:


> I get this on my plants too. Its not BBA. It never develops into the typical bushy BBA form, though it is related to BBA. Its black and it turns pink when dosed with Excel.
> 
> I call it black dust algae but thats just my name for it. I have no idea what it really is.
> 
> ...



Thanks for sharing, my plants where doing great, growing like crazy and then this happened and I trim, spray them with peroxide (helps), water changes every week 95%, excel everyday a cap full on a 55 gallon, etc and just like you said it just keeps on going....



JJVanier said:


> Looks like the start of some sort of thread/fuzz algae.
> 
> If you can confirm its algae there are some options to deal with it including, cutting your light duration to 4-6 hours, adding fast growing stem plants or floating plants to compete with the algae, increasing water change schedule, trimming the affected areas.
> 
> Dosing with excel, or spot treating with excel or hydrogen peroxide 3% are options as well but not necessary if you can nip it in the bud.


Thanks for the suggestions I'm already doing some of them!


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## Plantnerd (Dec 14, 2011)

None above mentioned advice would really help with the cause of the algae. 
Expect perhaps reducing the lighting period. But then you would have the algae again once you turned the light back to its original setting.

Your plant has an nutrient deficiency.
And untill you adress that the alage will come back. Floating plants, massive water changes, peroxide, trimming, fast growing plants..etc will not help with the cause of this problem. 
Some will even make it worse. 

I know nothing about your tank.. lighting, co2, fert..etc also it is hard to see 100% on the photo but it looks like BBA so your guilty plant deficiency is most likely co2.


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## dmagerl (Feb 2, 2010)

I cant vouch for if this is true or not but I read somewhere that plants start cannibalizing themselves when stressed. They break down their cells for nutrients and start leaking DOCs, dissolved organic compounds into the water column.

Where do they leak the DOCs? Along their edges.

Algae being low on the evolution scale are opportunistic and can make use of these DOCs exceedingly well. 

So where does algae grow? Where plants leak DOCs, along the edges.

So as Plantnerd said, fix whatever light/nutrient problem is affecting your plants and prune off the already infected leaves and the algae will go away.

BTW, I found that h2o2 & excel treatments do more damage to the plants than the algae does. And it always comes back if you havent fixed the original issue.


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