# EI and weekly 50% water change nutrient range



## plantbrain (Jan 23, 2004)

http://fins.actwin.com/aquatic-plants/month.200502/msg00076.html

This shows mathmatically that folks wanting to maintain a nutrient level that never exceeds 2X more than their dosing, 50% weekly water changes will suffice. This also assumes no plant uptake.

Given that this range is 10-20ppm NO3, or 1 to 2ppm of PO4, the main and largest variable is CO2, something much more difficult to accurately test and that plays a larger role when used in terms of plant health, algae presence and growth rates.

Many folks become complacent with respect to CO2. 
I do, Amano does, everyone. We assume the KH is the same, we assume the CO2 is good, all while folks spend their efforts measuring the smaller consituents.

When ever I question health of plants, CO2 is the first thing and is about 90% of all algae related issues.

When I started using higher light I started off realizing that the largest % of the plant's biomass would need to be addressed before I addressed the other lower % nutrients like N and P.

Therefore good critical measurement and maintenance of CO2 is the key to any nutrient routine.

Adding less nutrients can slow down the CO2 demand via slowing limiting growth and adding less CO2 can also slow down the nutrient demand in a similar manner. This has some limits before algae or poor plant health starts to occur and stability of these parameters is key.

Try maintaining CO2 at + or - 1ppm sometime.
Maintaining stable CO2 must be done in order to rule out confounding factors when addressing individual or combinations of nutrients that play a more minor role than carbon(40+% of the plant's dry weight versus 1.5% for Nitrogen for example).

A similar issue exist with respect to light and it's measurement. Perhaps even more so.

Regards, 
Tom Barr

3rd annual Plant Fest July 8-14th 2005!
[email protected] Get connected
www.BarrReport.com Get the information


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## cousinkenni (Jan 24, 2005)

Tom,

Not trying to be combatant..........but isn't the actual level that we dose each week more than 1X?

That math calculated the buildup over time dosing 1X of fertilizers. So if we normally dose 1X the maximum buildup using 50% W/C would be 2X (if we dose lets say 15ppm KNO3 the maximum buildup would be 30ppm).

Since we actually dose 4X a week, wouldn't the actual build up be 8X the normal dose? 1X 4 times a week = 4X. 4x multiplied by the factor of 2 gives us 8X? So if we dose 15ppm 4times a week we dose a total of 60ppm using that equation over time wouldn't we get a buildup of 120ppm of KNO3? 

But then again I don't remember calculus or have any idea of what you guys are taking about ;-) 

Ken T.


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## Jason Baliban (Feb 21, 2005)

Ken,
You are correct in this assumption, However you have to include plant uptake in your equation. The point is that the levels will never get to be higher then 2x the dosing with 50% WC.......and that is without plant uptake. So take what is left after uptake and times that by two and that is the highest your levels will ever be. If you dose 60ppm of NO3 a week - 45ppm or uptake, that is 15ppms*2......your no3 will never go about 30ppms. After a while of toms method you can slowly back off the ferts. Toms point is that extra ferts willl not cause algae and having not enough ferts will. Most peeps start on the higher level, but after a few months you will learn the uptake of the tank and be able to back off the ferts.
jB


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## cousinkenni (Jan 24, 2005)

Jason,

Thanks, but That wasn't the point that I was trying to make. 

The point I was trying to make is that it is possible to get a concentration higher than 2X using Tom's method (not that this is bad......look at my post, I wasn't knocking the system, actually I am now using his system).

The other calculations didn't include uptake and neither did I :neutral: 
I am just trying to keep things honest.

Ken T.


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## SAWALLACE (Dec 24, 2004)

It is possible to get into the 80+ppm range of nitrate, for example. You have to know how your bioload/feeding habbits affects your levels. Of course this applies to tanks with a decent quantity of fish in them, or to people who overfeed, but it is possible.


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## Laith (Sep 4, 2004)

cousinkenni said:


> ...
> The point I was trying to make is that it is possible to get a concentration higher than 2X using Tom's method ...


It's not possible to get a concentration higher than 2x your total weekly dosing, assuming a weekly 50% water change.


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## cousinkenni (Jan 24, 2005)

Laith,

What I am trying to POINT OUT is that you can get higher than Tom's 2X nutrient amount of 10-20ppm. From Tom's original post he makes it sound as if you can not get more than 2X the range of 10-20ppm when in actuality you can get as high as 120ppm. Tom never mentioned the "total weekly dosing".

I am saying this once again not to start controversy. I am trying to clear up a simple point so that if someone starts dosing in Tom's method, and god forbid actually test their water parameters they don't freak out when they see a reading that is really high instead of the 10-20ppm range!

Ken


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## Laith (Sep 4, 2004)

Ah! now I understand your point! :smile:


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## plantbrain (Jan 23, 2004)

I was waiting for someone to bite into that hook

I dose 10ppm 3-4x a week to a high light fully planted tank.
Adding more is nothing but wasteful. This is probably wasteful.

Do you need this much for _every tank_?
No way.

Most are fine with 1/2 this amount.
Most tanks are fine with fish load and 20ppm a week total NO3.
It's best to look at this from * a week NO3 total* since I suggested weekly water changes for this exmaple.

So if you had no plant uptake(and assume no fish input waste), then the max amount is 40ppm of build up.

Most tanks will be closer to 10-20ppm and stay there.

Many folks assume their NO3 test kits are infalible and accurate.
I suggest adding more like I do with PO4 to let folks know, hey, it's not going to cause algae and I assume the test kits are lower with respect to NO3, CO2 etc if folks are having trouble with algae, or plant health.

Given that algae is caused mainly by poor plant growth/deficiencies, CO2 especially, this approach is wise. Adding more nutrients will not harm anything and makes the target very wide and large.

My point here is that using these equations, you can accurately target any decent range you desire without a test kit and keep them there within a 2x plus or minus range.

Math fortuantely does not lie. 
Test kits most certainly do. But you can get around that with calibration.
But then you still have to test.

After testing a great deal, then what?
Mummmk.....you know the tank uses 20ppm per week when doing well.
So how much do you need to add to hit target range?
Do you still think you need a test kit?

I sure don't.
I like to see folks prove things to themselves.
Then they know.

If you plan on testing, you need to test all of the things to make sure the dependent variable is in line and not confounded by other variables.

Some variation, say 10-20ppm of NO3 and 1-2ppm of PO4 is easy enough to target and hit using EI with weekly routines.

So this allows you to test other things you might not have a kit available for(Light, many trace metals, organic fractions or precise CO2 measurements) and test them independently without testing all those other parameters each time. This saves enormous amounts of time, cost and allows you to test and focus on one thing at a time or a pair of variables etc. Precise stability is impractical and provides little gain(say 15ppm +, - 1ppm vs 10-20ppm).
You can test this is you want and see for yourself.

Regards, 
Tom Barr

3rd annual Plant Fest July 8-14th 2005!
[email protected] Get connected
www.BarrReport.com Get the information


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## plantbrain (Jan 23, 2004)

cousinkenni said:


> Tom,
> 
> Not trying to be combatant
> Ken T.


If you like plants, we are on the same side.
Never sugar coat it. Say what is on your mind.
And thanks for biting into it. The simple questions (obvious) are the best often.

I can tell when something is personal versus intellectual.
Intellectual attacks/debates are expected and welcomed.

I think many assume scientific rebuttals, arguements, debastes etc are personal, they are not ( well not suppose to be!). It's all good fun till someone pops a vessle in their brain thinking. You need to attack the arguement/theory, notion, idea etc with prejudice. Not the person.

Like a mosh pit with your friends. You still like them at the end of the show even though to the casual observer, they think you hate one another salm dancing into eachother. Or taking a friend out for a hell 4 hour Mt biking ride.

Slam dancing and science, awwwww...... ya gotta love it.

Regards, 
Tom Barr

3rd annual Plant Fest July 8-14th 2005!
[email protected] Get connected
www.BarrReport.com Get the information


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## cousinkenni (Jan 24, 2005)

plantbrain said:


> I think many assume scientific rebuttals, arguements, debastes etc are personal, they are not ( well not suppose to be!). It's all good fun till someone pops a vessle in their brain thinking. You need to attack the arguement/theory, notion, idea etc with prejudice. Not the person.


Tom,

With that being said, would you mind answering a few questions I posted for you in the "Algae specific problems" forum under the sticky "So why does New School = no algae"?

Thanks in advance,

Ken T.


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## BigFoot (Jan 3, 2005)

LOL! I never thought i would hear it put quit that way. Butt true.


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