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xtn1179 04-16-2012 06:28 PM

Type of Black Algae
1 Attachment(s)
Hi I have some type of black algae growing on my plants I have no clue what's going on. Please see the picture below and suggest solution. Thank YouAttachment 52937

Byron 04-17-2012 12:00 PM

To be honest, I can't make out the photo well enough to be certain. Any chance of a close-up of one bit?

I'd suspect it is brush algae, which is caused by too much light (intensity and/or duration). But a close-up photo may tell me more.

xtn1179 04-19-2012 05:51 PM

Type of Black Algae
2 Attachment(s)
Sorry about that.. here's a couple of new pictures.

I do a 10% water change every week
I add a capful of Prime every water change
a capful of Flourish Excel twice a week
a capful of Flourish every water change
a capful of Flourish Iron once a month

Feed the fishes once every other day during the middle of the day

My lighting are:

1x 36" T8 10k (on for 12hrs)
2x 34" T5 6700 (on for 8 hours)

Attachment 53077

Attachment 53078

please help. thank you

Byron 04-19-2012 07:00 PM

That is a form of brush algae, not the furry tufts we often see, but related.

First off, stop the iron. That may well be the culprit, along with light. Many think iron is needed for plants, but overdosing is easy to do because iron is a micro-nutrient. The iron in Flourish Comprehensive is more than adequate in a natural (low-tech) system. Adding any more without balancing with more of the other 16 nutrients is not going to be useful.

On the light, no mention is made of the tank size but I would suggest that the light is too long in duration if your only source of nutrients is Flourish Comp once weekly. And the intensity may be too strong, knowing the tank size and tube lengths/watts will help sort this out. Many factors play into this balance.

A side note on the Excel. I do not recommend this product. It is a chemical carbon supplement that does decimate some plants (Vallisneria for one, there are others), mosses do not like it much either. If overdosed it will harm fish. One of our members mentioned that it irritated his hand. I would not use it. Ironically it has been known to kill brush algae, at least when applied directly, but I would not advise this at present as I think the other two issues will solve this problem without risking plants and fish.


xtn1179 04-19-2012 11:12 PM

Type of Black Algae
Thank You.. the size of the tank is 55 gallon.

so basically cut down my light and when i do a water change just use the prime?

hopefully these will resolve the issues.

Byron 04-20-2012 09:41 AM


Originally Posted by xtn1179 (Post 1052769)
Thank You.. the size of the tank is 55 gallon.

so basically cut down my light and when i do a water change just use the prime?

hopefully these will resolve the issues.

No, let me explain. I now see the problems better, with this latest info.

First, the light. This is too much intensity, so I would reduce it. The T8 on its own will be inadequate, so the T5 alone will have to do. As for duration, this may need some experimentation. The goal is to have the light balanced with the nutrients so the plants are using all this to photosynthesize, and algae is out of luck. As soon as something is no longer available, plants slow and may stop photosynthesis, then algae takes advantage and increases. Perhaps 8 hours of tank light, with just the T5, is probably a good place to start.

To the ferts, you need some to balance this light, so use the Flourish Comprehensive once or twice weekly; dose the day following the water change, then (if needed) three days after that, each time at the amount on the label which for this tank would be about 1 teaspoon each dose. What wattage are the T5 tubes? I'm assuming they are Life-Glo tubes?

xtn1179 04-20-2012 01:08 PM

Type of Black Algae
Oh, I see. Ok, I'll adjust the timer on my lights and keep the T8 out.

My T5's are 34" ZooMed Flora Sun 39W each so that would be 78W total since I have 2 of them.

I'll do the water change today and add the dosage of Flourish Comp required.

I really appreciate all the help, thank you.

btw should I prune out some of the leaves that has the brush algae?

TwinDad 04-20-2012 03:43 PM

A capfull of prime is enough to treat 60 gallons, but you are only adding 10. I would consider only adding enough to treat the water added. Certainly no more than half a capfull.

YOu can remove them. IF the lowered lights does not promote algae it will die off, but it might add to the organics in the tank, so I would personally remove them. I don't know the percentage, but I would not remove every leaf save a few to keep it alive.

Byron 04-21-2012 10:28 AM

I agree on using sufficient Prime (or any other water conditioner) to treat the approximate amount of water added. A bit over is fine, I don't measure but I have a rough approximation of how much I squirt in. No point in wasting money, or in adding more chemicals and TDS [total dissolved solids] than necessary.

That light should be fine for intensity. The watts is rather meaningless, but I know those tubes so I have a fair understanding of their intensity and it will be sufficient.

Dose Flourish Comp the day following the water change. I'm not sure this is that essential, but Seachem did tell me that Prime would cancel out the trace minerals in Flourish, so waiting a day may have some benefit. I used to use Flourish at the water change, now I wait a day, but I can't say I have seen any difference.:roll:

On removing the leaves, remove the worst (any covered). But you don't want to remove all the leaves or the plant will suffer. From those photos, I would leave most of it.

By the way, one photo shows an Anubias (it is even flowering)...this plant should not be under direct light as it is notorious for getting brush algae in light. It needs shade, under floating plants is fine, or with an overhanging large sword or something. That would help too.


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