Another Algae ID

dutchy

Plant Guru Team
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Jul 6, 2009
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Hi,

I hope Tom or someone else can help me with this algae ID. It's only in the top 10 inch of the tank. Starts on leaves of Vallisneria and Amazon Swordplant after the leaves are around 2 to 3 weeks old. Rest of the plants are ok. To me it looks like staghorn. Am I right? What can I do? I've read a lot but I can't find out what's wrong. Pls help.

Dimensions 32 x 18 x 25 inch. 52 gallon effective.
118W T5, 12 hours total duration. light intensity is switched in three stages. 9 hours full intensity.
34 fish, none bigger than 2 inch.
External Eheim filter, 100 gal per hour at the outlet.
Very low surface agitation. Filter outlet is aimed diagonal from left rear to right front halfway down the tank.
Pressurized CO2, Dropchecker green. AM1000 diffusor inline with the filter outlet.
Plants start to pearl around 3 hours after lights on, at the end of the day it's like a champaign bottle. Cabomba grows an inch per day.
NO2 = 0
NO3 = 10
PO4 = 0,5
NH4 = 0,25
FE = 0,25 to 0,5
Addition of KNO3 and K2HPO4 according to Redfield Ratio
Addition of spores according to FE tests
Water changes 10 gallon every week

The algae grows, grows and grows. Pls help.

Regards,
HJ.
 

Philosophos

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Looks like staghorn algae (Compsopogon spp.) with what I'm thinking is a light undercoat of BBA along the edges.

Your NO3 is probably getting blown through fast with PO4 dosing like that. Decrease PO4 to something around half that, and start dosing around 15ppm NO3.

More importantly, turn your CO2 up. Even if you're using a 4dKH drop checker solution, you can still push things higher. Even with lower nitrates, CO2 is usually a bigger problem.

-Philosophos
 

dutchy

Plant Guru Team
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Jul 6, 2009
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Hi,
Thnx for your response. What I've done so far is:
- I started to add Flourish Excel 4 days ago. Now the algae starts to turn light grey. I hope that's a sign that it's dying.
- I started to add more CO2, I dropped the Ph every day 0,1 from Ph 6,9 to 6,7 now with Kh 6. I'm using a drop checker and expected it would turn yellow, but it's still green. Do you know how much I could drop it further? I'm kind of worried I'm going to kill my fish.

On the weekend I want to make up a 4dKh solution to get a better reference.

Regards,
HJ
 

Philosophos

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It sounds like the excel is doing its job; algae usually goes grey or red when it dies.

With 4dkh solution I can keep my drop checker yellow all day (by the time the adjustment period is over in the morning) and the plants looking healthy.

By the time you notice stress or the fish moving to the surface, you need to back off some. Don't just adjust CO2 and leave; watch them throughout the day. I even try to keep an eye on them the next day towards the evening.

Bubble counters are good for personal reference when estimating the amount added. Not 100% reliable by any means, but good for knowing how much you've added.

In terms of how much I'm moving the pH (again, not very accurate) in my own tank, it sits around 7.4 with the CO2 off. By the end of the day, the pH can be as low as 6.4, but averages 6.6 lately.

-Philosophps