MiamiAG

The discussion on the PPS thread got me thinking again. I know it's been discussed before. I don't think we have a definitive answer so lets give it another whack, college try, that sort of thing...

New school fertilization methods (EI and PPS) have certainly deepened our understanding of planted aquarium nutritional dynamics. They have allowed MANY more people to enjoy algae-minimized tanks.

The question is: why do EI and PPS minimize algae?

alexperez

IMHO I believe the reasons behind these methods are that the plants are no longer limited by any nutrients. And as long as the plants are growing the algae is kept at bay. Not very scientific, but my experience (see below) from the last 2 years have let me to believe this.



When I started keeping planted tanks, I read about the Sears and Colin paper about limiting Phosphates to stop algae growth. We’ll I tried that for a few months and always had BBA and fuzz algae. I kept the NO3 at about 10ppm and the PO4 below .5 ppm. While trying this method I got a bad PO4 test kit that was giving me high readings. We’ll I dosed at higher levels of PO4 (still thinking I was at .5 ppm) and the algae was getting less and less. My LFS in Arkansas tested my water and confirmed that my PO4 was over 2ppm. I got me another PO4 test Kit (La Motte) and Once again started the .5ppm Dosing and then the algae once again started appearing. I had to move to South Carolina so the tank was torn down.



In South Carolina I set everything up again and by now I had read about the EI method. So I started using it, and it working nicely. I had good plant growth and very little algae. I test almost daily (I Like to do it). And got a hold of a Bad NO3 test kit and instead of keeping up with the EI method, I believed the test kit more and so I dosed less NO3 than I should have. We’ll once again the algae came back. Once I figured that the NO# test kit Was bad. I gave up and bought all La Motte kits.
Once I started to dose and keep the NO3 at about 20ppm and the PO4 at about 2ppm the algae Once again stopped growing. We’ll it was Time to move again so I had to tear down the tank once more.




I set up the tank in Florida and everything was going great nice plant growth and no algae (EI Method). I now tested only once or twice a week and just dosed .5 tsb of KNO3 and 1.5 ppm of PO4 every other day. The test kits showed an average of about 20-30 ppm KNO3 and PO4 was always above 2ppm.
I recently had a mishap in the tank. After a water change for some yet unknown reason I lost about 70% of the Fish and about 50% of the plants. The plants that where left had stopped growing. And in a one week period I started seeing algae growing again. About 2 weeks after the mishap All the old and new plants where growing nicely again and the Algae stopped growing.



So from the above experience I concluded that any time the plants stop growing. Due to Lack of nutrients or for some other reason algae will quickly appear. Thats why the methods work they keep the nutrient levels that the plants need.

defdac

I believe, correct me if I'm wrong, that the whole purpose of this thread is the question why this is true: Why does unlimited nutrients and happy plants keep algae at bay?

MiamiAG

Correct!

There's a lot of very experienced and knowledgeable folks here. Let's hear your hypothesis, theory, conjecture, what not! You don't have to be right, just throw up your gut feeling.

S

MiamiAG

Because it is key to deepening our understanding of planted aquarium dynamics.

MiamiAG

Thanks Alex!

I agree with you that using the new methods results in algae limitation. The question I have is WHY do they work? If plant's growing well = algae limitation AND if algae and plants need the same nutrients (careful, I didn't say in the same ratio, levels, etc.), then can I conclude the following?

Good plant growth = algae limitation BECAUSE:

1) Good plant growth results in limiting a key nutrient for algae; or
2) Good plant growth produces some sort of allelochemical that limits algae?

niko

In the last 3 years I've had 4 tanks that were either free of algae or the algae was a direct result of something I did and the problem easily corrected. My opinion is not directly related to EI or PPS but I hope it has some merit. I'd say that in all 4 cases the plants had an "advantage" at some point and they "took over". How did the plants get ahead and how they maintained their dominance I can't say. Here are my assumptions;

Tank 1
Densely planted 55 gal. with extremely vigourous plants from the very beginning. The plants were grown for about 3 weeks in an unsual environment were they reproduced at almost insane rates. After transferring them to a tank containing 100% new Fluorite they continued the fast growth, but not at the same rate. About 2 sq. inches of hair algae appeared about day 5 and a blackout took care of them. The tank ran for about 6 months with no algae whatsoever, no fertilizing of any kind the first 3 months, and very lean additions of N and P later (NO3=2-3, PO4=0.25, 1 ml. of Fluiorish every 4-5 days). Water changes - 5 gals every week.
Assumption, advantages for the plants
The plants had the advantage of being very strong, not transported for days, and functioned 100% from the very beginning.

Tank 2
100% RO and 100% garnet (inert gravel, very much like glass). The algae appeared only if I overdosed a little or if I neglected to dose. Very lean dosing of N, P, Fe, Mg, and Ca.
Assumption, advantages for the plants
The fast growing wisteria in that tank used up all the available nutrients (not that much to start with)
The light was rather low - glosso would always try to grow vertically.

Tank 3
110 watts over a 25 gal., EcoComplete, Peat, Dupla Baccies. Narrow Leaf Java Fern, Anubias, Glosso. GH of 13 due to the EcoComplete. Very little fertilizing amounted to pale plants but no algae at all. Adding small amounts (N=3, P=0.25, Mg to bring the GH to 16, 10 drops Fe/TE daily) of PPS fertilizers and reducing the light period from 10 to 7 hours resulted in explosive growth. Only adding PPS fertilizers did not improve the situation. Algae (BBA, Staghorn) took over when I let the tank evaporate 50% but never appeared again when resuming good care.
Assumption, advantages for the plants
Luis magic hand.
Strong light limits algae, almost sterilizes the entire tank, but plants survive.

Tank 4
5.7 wpg, 100%RO, 100% garnet. Very little fertilizing in the beginning. Severe pale growth. No algae at all. Adding PPS fertilizers up to NO3=10 and PO4=0.5 + Fe/TE and Ca/Mg did not improve the plants. Reducing the light period did not change anything either.
Reducing the light to 3 wpg resulted in explosive plant growth even with no fertilization at all. No algae at all.
Assumption, advantages for the plants
Lack of nutrients limited the algae but the plants grew (pale).
Strong light limits algae, almost sterilizes the tank.

That's all folks!
--Nikolay

Simpte 27

After reading and re-reading numerous threads here, I have come to a few conclusions..............

Algae all need the same elements to thrive, though some do it better than others. I ASSuming this is why you can't differentiate why each one shows up in your tank. (IE........bba is caused by excessive... and green fuzz algae is caused by...) I do understand that it has to be introduced into your tank to begin with (ie new plants or fish).

CO2 increases plant growth which in turn allows plants to outcompete algae (Still don't know why increased plant growth means little algae if algae needs very little nutrients to the point where they are immeasureable on our test kits).

With this in mind, why doesn't algae always show up in tanks (or at least more than we see in healthy aquariums?)

IF one takes into account the theory of survival of the fittest (Usually the simplest creatures survive) Then why do blackouts work?

I'm really interested in everyone's opinions and theories.

Jason Baliban

Check out this thread. I think this is along the lines of what you are asking.
http://www.aquaticplantcentral.com/f...hread5514.html
jB