# My GDA battle



## Neo_sporin (Nov 10, 2006)

i've always read that green spot algae is caused by low po4 (phosphate). Have you tested you water for this?


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## esarkipato (Jul 19, 2005)

better question -- are you dosing phosphates?


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## plantbrain (Dec 15, 2003)

If you believe in the ADA nethod, no unless you use the high light ferts which have a little PO4/NO3.

But either way, GDA is not related to NO3/PO4, but rather light/CO2 near as I can tell, I know the NO3/PO4 seem not do anything either way.

Keep up on things after and clean the glass whether you think it needs it or not for 2 more weeks.

Regards, 
Tom Barr


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## BSS (Sep 24, 2004)

Man, does that sound familiar. I, too, just went through 4+ weeks of ignoring my tank. In the end, my tank looked just like yours, and now I wonder if it really was GDA. Though I've been irregular with dosing lately (sometimes missing 1 or 2 days), I have been regularly dosing 1/4 tsp of PO4 in my tank. I'm actually jumping up to 1/2 tsp in my 46g just to see if it really is PO4 deficient. I can't say that I really trust my Red Sea PO4 kit at this time (though, in the past, I've loved it). So, I'm not really sure where I stand on this one now. As my tap water has started having PO4 in it (around 1 ppm) in the last year or so, I don't think I'm PO4 deficient....but the GSA would tell me otherwise.

Grrrr...darned algae! But, it does help keep it interesting ,
Brian.


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## IUnknown (Feb 5, 2003)

Yeah, it's not a nutrient issue in my case. I'm dosing by the book, and it's always been a problem. One week so far, and it's looking good. We'll see how this works out long term.


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## Marc (Oct 13, 2004)

How long do you have the lights on for? 

I had the same problem when i was running lights longer than 8+ hrs a day.
I brought it down to 6 and it worked very well.


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## Hoppy (Dec 24, 2005)

My last GDA attack irritated me enough that I did a multi-weapon attack on it. First I did the let-it-grow-for-3-weeks cycle. Then, I drained the water down about 75% or so, and used paper towels to carefully wipe off every bit of it I could find, trying very hard to keep it all out of the water. I refilled the tank, redrained it back down and wiped it again, the filled it back. Next, I wrapped the tank with black garbage bags and left it for three days of blackout. Then I drained it back down again and re peated the wipe down, refill, redrain, wipe again and refill again cycle. I repeated that again after two days, then again after another two days. I also dropped my lights on period to 8 hours from 10 hours, and added a better filter - a H.O.T. Magnum 250, and made my venturi reactor (viewtainer mod) a more rugged device. Now, over a week later, after another water change and wipe down, no sign of GDA! Something in all of that worked, and I don't really care what it was, I am just delighted to be rid of GDA for now. Until I get too lazy I plan to do a big glass wipe down about twice a week, with a sponge scrubber, and a big water change about every other week. All of this with a continuous water change system working. This definitely keeps me busy enough to stay out of trouble.


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## danepatrick (Jul 17, 2006)

http://www.plantedtank.net/forums/water-parameters/37273-my-battle-against-algae-updated-11-a.html


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## skiboarder72 (Oct 13, 2006)

Hoppy said:


> My last GDA attack irritated me enough that I did a multi-weapon attack on it. First I did the let-it-grow-for-3-weeks cycle. Then, I drained the water down about 75% or so, and used paper towels to carefully wipe off every bit of it I could find, trying very hard to keep it all out of the water. I refilled the tank, redrained it back down and wiped it again, the filled it back. Next, I wrapped the tank with black garbage bags and left it for three days of blackout. Then I drained it back down again and re peated the wipe down, refill, redrain, wipe again and refill again cycle. I repeated that again after two days, then again after another two days. I also dropped my lights on period to 8 hours from 10 hours, and added a better filter - a H.O.T. Magnum 250, and made my venturi reactor (viewtainer mod) a more rugged device. Now, over a week later, after another water change and wipe down, no sign of GDA! Something in all of that worked, and I don't really care what it was, I am just delighted to be rid of GDA for now. Until I get too lazy I plan to do a big glass wipe down about twice a week, with a sponge scrubber, and a big water change about every other week. All of this with a continuous water change system working. This definitely keeps me busy enough to stay out of trouble.


Great to hear you finally conquered the mighty GDA 

Less light + more co2 did it for me


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## IUnknown (Feb 5, 2003)

I've been in the hobby long enough to know that GDA is not just 
something you have to live with in a tank, it has to do with something I'm 
doing wrong. I've had tanks were I just left them alone and didn't have 
signs of GDA for a month. I know my dosing is close because there is no 
sign of any other algae. So there are a couple of options to go with,

I can dose less and assume that what I'm adding to the tank is causing 
the algae.

I can dose more and assume that ammonia is causing the algae. This is 
because one of the things that I am dosing is the limiting factor. By 
dosing more, then plants are using up more ammonia and less is 
available to the algae. I mean, isn't this how reef systems operate, less 
algae because the Corals take up all the nutrients in the water?

Third, I can play around with the ratios of the Macros and Micros I'm 
dosing.

The other thing I haven't looked into is how much diffused lighting 
(PC's) compared to point source lighting (MH) has to do with GDA. All my 
GDA appears on the glass, is this because the reflected light of 
diffused lighting falls the most on the tank sides?


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## plantbrain (Dec 15, 2003)

I just got some GDA from a friend.

I added it to one tank and it's doing well.
There is an identical tank above this one. It has the same things done to it and the same plant biomass.
Same light
Same CO2(more on this)
Same plant biomass
Same filter
Same tank and size
Same substrate(ADA AS), same age
Same fish load
Same dosing/water chem.

It took about 4 days to see the GDA develop.
Both tanks got inoculated.

There's nothing significantly different near as I can tell.
CO2 is the biggest issue.

So with the KH ref membrane on a pH probve etc, I hope to see what changes are able to induce it and grow more of it.

Mike Rubin from SFBAAPS was the first person we noted who had this alga.
He has 110 w on his 50 gal.
I've noted a light relationship, warmer temps, sunlight increase growth rates, higher light = more GDA.

I've seen it bloom and then go away with good routines and tank maintenance in a coulpe, of my own tanks. Never really lasted more than 3-6 weeks.

Adding the sunlight or very high light seemed to cause it to bloom.
I think there's some combination effect and it's not too clear, you generally need decent conditions for it to occur.

Regards, 
Tom Barr


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## thadius65 (Sep 15, 2006)

IUnknown said:


> I've been in the hobby long enough to know that GDA is not just
> something you have to live with in a tank, it has to do with something I'm
> doing wrong. I've had tanks were I just left them alone and didn't have
> signs of GDA for a month. I know my dosing is close because there is no
> ...


IUnknown,

Hmmm... you might be on to something with your comment on type of lighting. My lighting is as follows:

2-36" Aquasun 95w VHO's (10,000k)
1-48" Aquasun 110w VHO's (10,000k)
2-30w Lights of America screw-in CF's (cinabun shape - day sun 6500k)
2-20w Lights of America screw-in CF's (U shaped - day sun 6500k)

I noticed that the GDA is mostly (really bad vs just a bit) in the area of where the CF's are located. Since they light 360degs a good portion is hitting the front of the glass. I do have the underside of the canopy flat white, but there is still more glass hit of that light than the VHO tubes.

Ted


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## Hoppy (Dec 24, 2005)

All of the GDA I have had has been the worst, by far, where the light on the glass is the strongest. So, I have no doubt that light is the key factor. Whether or not the diffuse light from PC bulbs is a factor I don't know.

I have been calculating and recalculating my fertilizer dosing. I got my CSM+B back when Greg was selling it with extra iron, which he no longer does. So, it occurred to me that my dosage might be adding too much iron. Unfortunately, Gregs site no longer mentions that mix, and I don't know how much extra iron is in it, but I recall he doubled the iron amount. So, I am starting today to dose half of what I usually dose, just to watch what happens. I suspect I will see nothing different, but who knows? I'm mentioning this only because of the suggestion that CSM might be a factor in GDA and that led me to look at whether or not I was excessively overdosing it.


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## IUnknown (Feb 5, 2003)

A little update on the tank. I've tried everything suggested to deal with the GDA. Lights are down to 8 hours a day and the pendant is now 10" from the surface of the water. So I bought some algae fix and I am going to nuke the tank. If the algae fix actually deals with the GDA, then when I stop using it, if the GDA returns, then it must be something wrong with my dosing schedule.


Well no luck the first week. I'm hoping the algae fix takes a couple of weeks to kick in, otherwise this algae is indistructable.


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## IUnknown (Feb 5, 2003)

Finally, first week with out GDA. was the second week using algaefix. The only other changes I made from recommendations from other people are the following. Dosing schedule was
Po4- .5 ppm every other day
No3- 4 ppm every other day
Flourish - 5 mL every other day
Changed to 
Po4- .25 ppm every other day
No3- 2 ppm every other day
Flourish- 3 mL every other day
Don't really think such a little change does anything personally. I set the Co2 to come on two hours before the lights come on. Maybe the algae was taking advantage of the light early on as the Co2 ramped up? I also replaced the filter floss when I did a good clean, assuming lots of GDA could build up in the floss. I'm going to run the algaefix for a couple more weeks and then see how it goes from there.

My cherry shrimp are being very patient during the whole process,


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## IUnknown (Feb 5, 2003)

So after the discussions on Tom's board, I'm wondering how much of my problem was Co2 related. Maybe rather than recommending the wait method, we should also make sure people are running Co2 a couple hours before the lights turn on. Start experimenting with that to see if it is an issue. I've noticed stunting on the tips of my stems, and never bought into the Ca deficiency issues. Maybe this was my problem?


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## actioncia (Jun 9, 2005)

What size tank is this? A nano? Regards, JC.


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## IUnknown (Feb 5, 2003)

A 20 gallon. The tank with the shrimp is a hospital tank. I ended up stopping the use of the algaefix cause the shrimp were dying off in the hospital tank. So lets see if the GDA comes back next Thursday.


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