# GDA - and the MCI method



## barbus (7 Oct 2010)

hi,

As the title says i have this algea GDA and i cannot get rid of it, every time i scrape it off it keeps coming back in max 3 days.I've read about this algea alot , and i honestly  don't want to  use the first method of killing it, i think there is not much annoying thing then to let this yucky thing on the glass for a month or even more until it finishes its full cycle and covers the whole glass so u can't see inside.
I just don't wanna use this method beacuese i 've read about another working method wich is called the MCI ( method of controlled imbalance) apparently giving results in this case too ( saw in other forums) , so i thought i give it a try.
The method says as far as i understood ( please correct me if i'm wrong) to use the No3 protocol wich means the following:  get the Fe and Po4 as low as u can possibly to 0 by a large water change, then start to add only KNo3 every day until u get GSA ,( and of couse keeping or CO2 at max)  ... at the point GSA appeared on the glass u stop with the KNO3 protocol and start with the Po4 protocol to eliminate it ( gsa) .  If i'm getting well when the GSa appears no other algae can flourish or all any other types dies. This is all ok and nice but i still do have a lot of questions.
1.  Do i have to add only KNo3 and no other macro nor micro during the protocol,?
2.  Won't the plants show deficiencies during the protocol if i dose only No3? ( for example if i used to dose EI there gonna be huge deficiencies IMO) 
3. What is the shortest time one can get rid of this algea with this method?
4. GDA is flourishing when there is an inbllance between Ca and Mg perhaps Po4 too ...
Could i solve this algae problem by simply resolving the correct ratio between Ca and Mg  like 4:1?

here are some datas of my tank: 300L  heavily planted , pressurized co2 with external reactor, 0.7w/L, EI fertilizing, weekly 50 % wc.

I Really expect some useful information on all this ,
thanks.


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## plantbrain (8 Oct 2010)

If you look at his tank, it's really too much light and it's not that nice looking.
Also, it's rather test, dowse and wait and see, takes a lot of time and runs around the real issue.

Trade one algae for the other and does not result in it never coming back again.

I have spent a lot more time inoculating GDA and other species than nearly anyone else, not just with one tank, rather, several. This gives me a lot more statistical power to compare and make sure I'm not over looking something.

Algae cure all methods are popular for good reason: they prey on the desperate.
They really do not focus as much on the real issues and look at the holistic issue of plant growth.

Most focus/have a very nutrocentric view point.

They do not test or measure light with any error associated, let alone CO2.
Clearly, these two factors alone play a massive role with respect to plant growth, and indirectly.....this leads to algae issues.

I suggest lowering the light intensity 1st, then focus on CO2, lastly...nutrients. Why? This is how photosynthesis worsk and how plants grow, the process does not start with nutrients :idea: 
Light => drives CO2 demand= drives nutrient demand, not the other way around.

Less light= more wiggle room with CO2= less algae issues.
The only tanks that where able to maintain GDA for any time had higher light and poor cO2, the others even with repeated inoculations never once got any such algae(this is also true for various other species of algae).

By correcting the light and adjusting the CO2, the algae went away in the test tank, the algae never because an issue in the reference control tanks that where repeatedly inoculated. Algae was present in both tank test, it just did not establish on the control.

Nutrients where high in all tanks, thus independent.
Dependent variables where light and CO2.






I'm running 1.5w/gal here, a tad less, and the distance is over a meter to the hair grass.
Or about 30-40 micromols. CO2 is about 45ppm for 8 hours of the day.

This was a test tank:




Algae cleared up easily once the CO2 was corrected and the light reduced to 30-40micromols.
Prior it has about 18-22ppm CO2 and about 60-80 micromols.

Adding non limiting ferts except PO4 is nothing new....... PMDD suggested it 15 years ago.
It leads to GSA, which we can get rid of by dosing PO4 back up again, cycling through all the other species can work I suppose............but it is a very roundabout way to cure algae and really does not "cure it"........just trades one for another species.

The real solution to algae is learning how to grow plants well.
Always has been and this will never change. Has not since I got into the hobby 30+ years ago.

Regards, 
Tom Barr


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## barbus (8 Oct 2010)

tnaks for you help,

I'll wiggle on the co2 sytem and I make sure I have a better co2 circulation on the water and keep you up with the changes.
I think I'll postpone the sulotion i mentioned first. 

I also reduce the lighting to 0.5 W/ L if that would be enough. 

I light the tank 8 hours a day with 2 hours pause ( 4 hours on , 2 pause and 4 hours on again ) , 
do you think this make any difference to plants or algaes or its just an useless mith?


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## CeeJay (8 Oct 2010)

Hi barbus
I wouldn't have a 2 hour break in the lighting myself. This is not good for the plants as the plants energy production line has to start up twice a day, wasting energy, hence slowing growth.
Algae will respond far quicker to these sort of changes, especially if your CO2 is not right. 
Mother nature doesn't turn the Sun off at lunchtime does she   .
If you have the break because you want the lights on for viewing later on, I would just move the whole lighting period to start later. In fact I did, my lights come on at 16:00 and go off at 23:00   .


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## plantbrain (8 Oct 2010)

0.5w/L might be too high even, try .4 to .35 range.
If the lights are T5's this should be plenty.

You can screen the light also, add metal window screen and layer it to reduce the light also, the shade cloth idea.


Regards, 
Tom Barr


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## Garuf (8 Oct 2010)

Tom, My lighting works out at .38 wpl, 122l 2 x 24w t5 (no reflectors as such), how do you think this would equate in terms of par? Is it going to be enough for hc etc? A lot of people are suggesting the par would be in the region of 10-20ish and therefore too low, true/false? I just don't want to throw money at plants that I can't keep without upping the light. I've seen a lot of people have had good growth with similar setups but none of the tanks I've seen have had stems or the highlight high 
co2 clichÃ© plants being all low lighters, crypts and the like. I know George had a very similar set up but I seem to remember it being again, all low lighters. This is the reason I'm so keen to get my hands on a par metre to asses it for myself. 

ps. sorry for the hi-jack


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## barbus (9 Oct 2010)

plantbrain said:
			
		

> 0.5w/L might be too high even, try .4 to .35 range.
> If the lights are T5's this should be plenty.
> 
> You can screen the light also, add metal window screen and layer it to reduce the light also, the shade cloth idea.
> ...




I can easily reduce the light to 0,3 or 0,4 W/L in no time , but what really concerns me is that the tank is 50 cm deep , very densly planted ( dutch style) ... won't the lower parts of plants  get black or even rotten ? 
This happend when i reduced the light last time... or this is have to do with co2 distribution too? 
And yes the tubes are T5 ( 54 w aqua medic plant grow) .
Sorry for my bad english    .
cheers


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## plantbrain (10 Oct 2010)

Garuf said:
			
		

> Tom, My lighting works out at .38 wpl, 122l 2 x 24w t5 (no reflectors as such), how do you think this would equate in terms of par? Is it going to be enough for hc etc? A lot of people are suggesting the par would be in the region of 10-20ish and therefore too low, true/false? I just don't want to throw money at plants that I can't keep without upping the light. I've seen a lot of people have had good growth with similar setups but none of the tanks I've seen have had stems or the highlight high
> co2 clichÃ© plants being all low lighters, crypts and the like. I know George had a very similar set up but I seem to remember it being again, all low lighters. This is the reason I'm so keen to get my hands on a par metre to asses it for myself.
> 
> ps. sorry for the hi-jack



Sounds about right for HC, you do not need much, I used this much at 1 meter away from the plants total distance.





10-20 is a bit too low, I do not know of any plant that can live submersed at less than 12 micromols, Hydrilla is the low light winner. 25-30 is pretty low overall.

Regards, 
Tom Barr


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## plantbrain (10 Oct 2010)

barbus said:
			
		

> plantbrain said:
> 
> 
> 
> ...



My tanks above are ALL 60cm + deep, then another 25-30cm the lights are above that!

So about 1 meter away of so.........,if the lights are spread out, then there's no issue, if they are just all bunched together, they are less efficient.

Good CO2 will allow you to use less light, while getting more efficiency out of that light.

Read here:

http://www.tropica.com/advising/technic ... light.aspx


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## Garuf (11 Oct 2010)

Thanks for the reply Tom, basically it confims that ideally I need to get my hands on a Par metre! Though, I've been wrong before, like you say, it could be spot on.


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## barbus (14 Dec 2010)

sorry to say this but I had no result by rising the co2 level ... I kept it stable for weeks  at 30 - 45 ppm 
( very light green with a 4dkh dropchecker)  and the GDA unfortunatly had not dissapeared ...at all.
Oh yes , the light was also reduced to 3W/ L ,.... any suggestions?


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## smik (16 Dec 2010)

Hi Tom,
has the same effect reduction lenght of the photoperiod ? 
Or is it better to reduce lighting intensity ?
0,5 W/L - 6 hours   vs.  0,32 W/L - 8-10 hours


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## ceg4048 (6 Jan 2011)

barbus said:
			
		

> sorry to say this but I had no result by rising the co2 level ... I kept it stable for weeks  at 30 - 45 ppm
> ( very light green with a 4dkh dropchecker)  and the GDA unfortunatly had not dissapeared ...at all.
> Oh yes , the light was also reduced to 3W/ L ,.... any suggestions?


Hi,
    Well the problem is that CO2 does not kill GDA. GDA loves CO2 as much as plants do. having good CO2 and flow distribution helps you to prevent an algal bloom but once the algae is there it has to be gotten rid of by other means. That's what makes CO2 related algae so problematic. You could try a 3-4 day blackout no nutrients and no CO2. Then return to good CO2/nutrients for a week and repeat if it reappears.

3 watts per liter is a phenomenal amount of light. Are you sure you don't mean 0.3 watts per liter?



			
				smik said:
			
		

> Hi Tom,
> has the same effect reduction lenght of the photoperiod ?
> Or is it better to reduce lighting intensity ?
> 0,5 W/L - 6 hours   vs.  0,32 W/L - 8-10 hours


Intensity is what does the damage. Always try to lower the intensity as a first option.

Cheers,


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## plantbrain (16 Jan 2011)

CO2 and light does not effect what is already there, it only prevents reoccurrences.
I attack it good and and it takes a few times but it is not as fruitless like when the CO2 was lower/light higher.

Still, I can offer no other plausible explanation for the lack of inoculation and germination in the other 4 aquariums I have and dose the same, have the same PAR, bulb types etc. CO2 is about it. With the high tech CO2 meter, there was a 20-30ppm difference btw the two.

This does not imply cause, however, but I cannot rule it out either.

This is far far more experimentally sound that running around playing with nutrients since I actually have 4 controls.
MCI has no control and we can offer explanatory rational for why the algae stages go from one to the next.

Many have already done it. I suppose for some who are really impatient and less concerned about the long term control/horticulture, it offers some use. But with that attitude, you got bigger issues with scaping and control of growth.

GDA seems to have appears about 7-8 years ago, it was not noted much prior.
I've not found it an issue for my tanks but many hate it.
And is often the case, these folks get pretty desparate, so they will do and try everything but often miss the point that good plant growth/health etc= little algae issues, the 4 controls illustarte that even with repeated inoculations.

 This does not help you if you cannot provide that, so it's tough to believe it.
But you can see that I do not have any issues with GDA nor need to do this run around with nutrient s either, so do most other folks in the know as well.

So that's something to consider ye of little faith  
Finding true cause is much harder.

Regards, 
Tom Barr


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## barbus (10 Apr 2011)

3 watts per liter is a phenomenal amount of light. Are you sure you don't mean 0.3 watts per liter?



thanks for correcting me ,  yes I meant 0,3  w /L ...


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## niru (11 Apr 2011)

My 180 litre also had GDA on the front glass, and no matter how I cleaned it, it reappeared back. Then I read here (some other post) what Tom had already suggested: ignore it for about 3 weeks (its lifespan) and then clean the hell out. With other things in line, it shouldnt reappear..

I tried this, and it helped. However, come spring I saw this stuff coming back. my tank is the winter garden and gets enough ambient diffuse sunlight on the front glass. As a check, I partially covered the glass after a WC, and watched the reappearance ONLY on the light-exposed glass. So now I cover the full glass during daytime, and GDA is no more!!
My lights turn on only at 14:00 hrs and run till 23:00, so I can appreciate the tank better after coming from work 

Hope this helps.

-niru


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## plantbrain (15 May 2011)

Some folks have notice that their Mg was low and they where not adding it. After adding it, the correlation was the GDA went away in a couple of weeks. This is correlation, not cause. 

However, it does show that many factors that reduce plant health, even if seemingly mild, can have a pronounced effect.

So the goal is more to improve plant growth/health and focus on the plants, not the algae. Algae is just symptomatic of a larger plant growth issue, even if the aquarist does not see it. I've never once found any evidence otherwise, Amano will say a similar thing, as will some of the world's top scapers.

Mg is often overlooked and bundled into GH in general..........and it's fairly critical to growth and chl a and b etc.


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