The Ei Method

[oldwhitewood]

One thing that confuses me about EI and I was thinking about this in the car. In the past I have always used fast growing plants such as hygro etc, I've found when these plants are growing they are a brilliant defence against algae and really take care of the tank. As of course you guys know already. But most of my tanks have never been long term, this is due in part to me never being satisified with the aquascape comparing it to Amano and obviously falling short. It's also due in part to either algae taking over or the plants stopping growing. I think this has been due to lack of nitrates.

What I am having trouble getting my head round is this, the plants are using up nitrate and phosphate ok which they need in order to grow and outcompete the algae, now if you have low levels of nitrate and phosphate how is it the plants dont use them up straight away and further starve out the algae?

Let me explain what happened to me recently, my tank was growing quite well, its a rio 125 with two power compact 36w dual daylight T5s and pressurised CO2, about 30mg/l. The tank is planted with e tenellus, glosso, microsorum, hairgrass, java moss, vallis and apongeton crispus (spelt wrongly I think), anyway there was no algae apart from some on the glass. Now I had been using rowaphos before, but it was quite old and probably not very effective, so I decided to remove it replace it with a new bag. So I took that out and also started dosing liquid ferts from ADA, within a week my tank was infested with hair algae. Now I think this is due to before there being enough phosphate in the water because my tapwater is high in phosphate, plant growth wasn't as lush as it could have been and this I put down to a lack of nitrate, so what happened is the new rowaphos took out all the available phosphate and suddenly the algae took hold of the tank. Does this sound about right? Now I am trying to dose using the EI method to see what happens, as I confess I have never really followed it before but tried to achieve the same balance on my own. Anyway yeah better that this happens now than in my new tank.

Another thing that confuses me, say at the start of the setup you use lots of fast growing plants, later on you want to remove them to have a different plant in their place, so rather than having hygro in the tank you want to remove it and put in c helferi or elocharis, what happens at that stage?

 

[George Farmer]

Good question - well presented.

This is my (limited) understanding of the whole concept.

EI's principle is to give all the plants more than enough nutrients in order for them to grow well (for example in nature most aquatic plants only require 2ppm NO3 but we dose up to 30ppm or more quite safely) - this is known as "luxury uptake". Plants can use far more nutrients than necessary.

Plants that grow well, slow and fast growers, easy and demanding, beat off algae. Not because they out-compete for nutrients but because there are more complex bio-chemical processes involved. This out-competing concept is old-school and is why many still believe that very low NO3 and PO4 levels are a good thing.

We still do not fully understand what these processes are or how they work. One school of thought is alleopathy. In my algae article I refer to alleopathy but its role in algae control isn't scientifically proven. It does however illustrate the concept of growing plants versus algae quite well.

When starting out it is important to plant with fast-growers to help establish a bio-chemical "equilibrium" where algae doesn't get a look in - a newly set-up tank is especially at risk because there isn't the necessary established processes (that we still don't understand). Once the equilibrium is acheived you can switch to slower growing, more demanding species without risking algae because these processes and the resultant alleochemicals (or whatever is at work) have "matured".

Hope this makes some sort of sense. EI is the cutting edge in this hobby. zig may be able to elaborate or give his take on the subject.

 

[oldwhitewood]

Ahh right I see, I think I understand. I'm thinking of the plants having a limit, kinda like a saturation point where after this it cant take in any more nutrients, this is obviously not the case it must be that the process refines itself more and therefore the plant grows and develops. I think...hmm its been a long day I think I better lie down, brain hurts.

 

[Andrew G]

THis is a dumb question, but being new to the hobby, what does EI stand for?

 

[George Farmer]

what does EI stand for?

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