# black algae



## blue_d (29 Nov 2007)

Hi
Sorry but my first post is about algae! Hope you can help and promise to do better in the future 


On older leaves of my plants - particularly amazons and java fern - I'm getting this black hard coating.
Here's a picture of an amazon leaf




 

Any ideas on the name or what I can do to get rid?

thanks
David


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## ceg4048 (29 Nov 2007)

Hi David,
                It looks and sounds like possibly GSA (green spot algae) which is one of the most hated of all species because it tenaciously hangs on to whatever surface it is attached to. There are some standard procedures but it would be better if we could get a fundamental understanding of you tank characteristics, your maintenance procedures and most importantly your fertilizer dosing procedures.

Could you answer the following questions?

1. What size is the tank?
2. How much light, what type of light (T8? T5?), and what duration of lighting do you have?
3. How long has the tank been running?
4. What type of substrate are you using?
5. What nutrients, in what quantity and with what frequency are you currently dosing?
6. How often to you do a water change and what percentage of the water do you replace?
7. What type of filter do you have and how often is it cleaned?
8. Do you inject CO2 or do you use any carbon supplements?
9. What is you fish loading and how often do you feed?

Sorry about all the questions but the better idea we have of how you run the tank the better able we are to suggest tweaks
 

Cheers,


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## blue_d (29 Nov 2007)

Here goes:

1. 48x18x21(deep) inches - 65 gals / 300 litres

2. Arcadia T5 luminaire - 4 x 54w. 2 bulbs (108w) running for 9.5 hrs with the other 2 (108w) running as well for 2.5 hours in the middle of that period

3. Tank running for nearly 3 years

4. Aquagrit substrate

5. 2.5ml iron weekly, 5ml Seachem Flourish weekly

6. 20% water change every 2 weeks

7. Eheim 2026. Rinsed through in tank water every 6 weeks. Fine wool filter pad changed each time. Contains Efimech and Efisubstrat.

8. No CO2 injected. 5ml Flourish Excel daily

9. 40 inches of community fish - including 2 Otos, 2 SAE's, 2 pepper corys. Only fed lightly once per day.


I've had this black algae for many months. The tank runs along well and I'm generally happy with the water quality. I get pretty strong growth on my large Amazons and java fern, but the top sides of the older leaves soon darken with this stuff. It does not scrape off - seems perhaps to be in the leaf cells itself.

Thanks for any thoughts / advice


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## daniel19831123 (29 Nov 2007)

If it's a heavily planted tank, I got a feeling that the macro might be on the low side. Without CO2 injection in this lighting is not making situation any better as well... I might be wrong though. The plant won't have a fighting chance against the algae if there is other limiting factor around.


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## ceg4048 (29 Nov 2007)

Hi,
    Well, the lighting seems to be in order, the tank is mature and maintenance practices sounds impeccable. Nothing else looks out of order except that as the plants get more massive their nutrient demand would increase and so it's possible that their NPK demand can't quite be satisfied by fish waste and substrate alone. I'm tempted to say Phosphate deficiency but if you aren't dosing any macros at all it could be a combination of two or all three.

I'm a macro zealot so I typically suggest perhaps at least once a week dosing of an NPK product of choice. Many now seem to be using the Tropica TPN+ which has traces just like Flourish and has NPK as well. You might also try browsing the AE site and obtain the individual dry salts (KNO3 and KH2PO4) which is less expensive. It's possible you may also need to increase the excel dosing as well, but if you're not comfortable with that then just try adding the NPK for a few weeks and see how the plants respond.

In any case cut all infected leaves out of there to help the plants recover and to reduce the uptake demand. When your noon burst of light goes on it increases the nutrient demand for that 2.5 hour period, so you may want to consider disabling 1 or both those bulbs until you fix the nutrient problem.

Cheers,


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## blue_d (30 Nov 2007)

thanks very much for your help - I'll go and investigate the world of macro dosing. Any pointers on where to go for comprehensible / reliable info?


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## ceg4048 (30 Nov 2007)

Hi,
      Easy, check the Aquarium Fert Dosing sub-forum and read this sticky: http://ukaps.org/forum/viewtopic.php?t=13

It's exhaustive and it mostly targeted at highly lit tanks since 
these tanks are more prone to nutrient deficiency.

A quick macro primer:

Nitrogen (N), Phosphorus(P) and Potassium(K) (as well as Carbon) are the macro nutrients and are what plants mostly need. The so-called "micro-nutrients" or trace elements as they are also known are found in the Flourish that you use. They are referred to as "micro" since plants only require very small quantities of these elements such as Iron, Manganese Copper etc. Plants really depend on the macro nutrients for survival. These 4 elements N P, K and C are the building blocks of plant physiology. 

N - Nitrogen is the primary element of which chlorophyll is composed. 

P - Phosphorus is a component in DNA and cell membrane and so is key in many growth functions.

K - Potassium is used in almost every plant function. It promotes photosynthesis which generates the formation of carbohydrates,oils, fats and proteins and then it also is used to transport these products to storage locations such as seeds and roots. Potassium also is used to enhance the efficiency of Nitrogen, enhance the absorption of water, and in the development of roots.

If you are not dosing these elements then the plants have to scrounge for whatever they can find dissolved in the water  column (from tap water) or in the substrate. Nitrogen is the easiest to find probably because fish waste or decaying food generates NH3 (ammonia) so the plants can absorb and process  this from either from soil or water. K and P are probably in the foods that you are feeding to the fish so this may also be available in small quantities. Because your lighting is reasonable the demand for these products isn't as high. As I was saying earlier though, as the plants grow they need more of everything so for a while you were actually dosing these but it's likely that the plant growth is starting to outstrip what you are feeding.

Macro nutrients are widely available. The basic choices are either to buy commercial products like Seachem Nitrogen, Potassium etc, or Tropica Plant Nutrition+ which is very good because it has macros and micros. The other option is to purchase the dry potassium nitrate KNO3 and potassium phosphate K2PO4 and dose these individually. A popular place to buy these online is AE; http://www.aquaessentials.co.uk/

Have a look at these links and if you have any further questions just let us know.

Cheers,


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