So, why does New School = no algae?

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.

Why do these methods work in contravention of what seems to be found in nature?

Using simple aquarium test kits, I have measured PO4 and NO3 levels in healthy lakes which support an abundance of aquatic plant life. The PO4 and NO3 levels were too small to be measurable - nothing like as high as the levels commonly encouraged in the planted tank hobby. In these locales the lake water was very healthy, clear, not eutrophic. Algae types were neither dominant nor obvious.

While it is difficult to compare a natural environment such as a lake with an aquarium - lakes have thermal zones, areas of run-off, large dilution factors, large surface areas for gas exchange, relatively cool temperatures, and other features that aquariums do not have - the main difference I notice is that lake water is ALIVE. In aquariums, it has a tendency to become DEAD quickly, particularly as a result of chemical manipulation by the inexperienced aquarist.

IME / IMO it is all about water quality rather than nutrients - at least that is the way I tend to analyze and understand the problem or avoiding algae.

Algae prevail in DEAD water. Water changes rejuvenate the system. EI-style, which evolved in times before many people had spreadsheets etc, uses targeted dosing levels and water changes to ensure water quality is optimum. Water changes allow for unknowns to be addressed and buildups to be avoided. PPS is an analytic approach which hinges on providing enough but not too much, so as to ensure optimum water quality while having minimum water changes. When a PPS proponent fails in his/her dosing regime, they do a water change.

Nutrient dosing is just a part of the water quality story.

(Now if only that SAVE AS DRAFT button was down there I could have saved you from reading this embarrassing Plocher-like plonk).

Andrew Cribb