EI testing strategies

sawallace · Mar 19, 2005

Hello everyone,
I am new to the EI method. As I am still new, I am concerned about adding too high a dose and possibly "compounding" levels over time. I still do not understand the "re-setting" math and I'm hoping you can simplify things for me. At first week’s test, my levels were extremely high. Obviously this means I am dosing too much, but how much?

I plan on testing right before my weekly water change until I get the hang of this method. What values should I be looking for? E.g. Top end of the range? Slightly above the range? Midrange? Is there an upper-limit?

Perhaps you could suggest some strategies for testing for those of us who are still new to this.

Thank you,
-Scott

Tom Barr · Mar 19, 2005

Re: EI testing strategies

Scott,
What is your tank size, KH/GH, lighting?

The EI suggestions are top end, they don't cause algae or fish health issues, but they are not needed if you have less light, mainly slow growers etc.

So if you feel better with less, there is nothing wrong with that.
As long as there is enough for the plants, things are fine, it's when the nutrients run out that it creates a problem and algae(except NH4/CO2).

Regards,
Tom Barr

sawallace · Mar 19, 2005

Re: EI testing strategies

Hello Tom,
Your top end values are what i'm aiming for, however, my params are borderline dangerous to my fish.

Is the top end, the absolute "top end" if tested at any given time?

My tank is 50gal with 4wpg. Mostly slow growers, swords and hairgrass. I'd say it is med-heavily planted. It could be a chemistry problem, I tried to make up a solution with dry ferts measured in grams rather than just adding tsps.

The following would be acceptable to me:
CO2 range 30-40ppm
NO3 range 20-30ppm
K+ range 10-30ppm Not measurable, so a guess.
PO4 range 1-2 ppm
Fe 1ppm or higher Not measurable, so a guess.

My test for NO3 and PO4, for what they're worth, were much higher.
KH/GH/CO2/Ca/Mg all seem fine.

I was more looking for an ideal way to test the tank. For example right before a WC, right after a WC, midweek... after ferts, before ferts, etc. Also what range is acceptable for the test? Since EI doesn't dose the same every day, i.e. WC/macro...micro...macro...micro...macro...micro...off, i was thinking there would be a strategy behind testing. I'm assuming the levels should either be on the upper or lower limits depending on if it's a dose-day or off-day.

The idea of not eliminating guesswork through math and WCs is what attracted me to EI. The ideal being not having to test, but for now, as a beginner, I really need to. (Which my water tests have shown
)

Tom Barr · Mar 19, 2005

Re: EI testing strategies

So what type of test kits are you using?
In order to have any sense of confidence in a test kit, you need to know if the result they give are accurate ansd reproducable.

Otherwise they send you off on a wild goose chse that I have seem many people go down, sometimes for several years or longer..........

Generally upper range kits, Lamotte and Hach are what I suggest.
Some claim certain cheapy brands work just as well, I'm not conveniced.

You can test the kit against a known standard you can make with DI water and the chemicals, better yet a series of standards over the range of interest.

While testing might seem like a good idea, it can also cause more problems if not used properly and calibrated.

Now you can do that and get somewhere with your test kits.
If you are doing 50-60% weekly changes, it's unlikely you'll go beyond the ranges I've suggested, not that going beyond them will harm fish, you need to get quite high, I honestly do not know HOW much is too much, I've gone to 75ppm NO3, 3-4ppm PO4, 100ppm K+, 2-3 ppm at least on Fe/traces, GH of 25, KH 15 etc.

Do you need this much? No, you can get away with less, there's no rule that suggest you cannot.

These are just max rates for even the most finiky of weeds.
Some plants need more than others, when the levels of NO3 are low, some plants have trouble.

Same with poor use of CO2.

You can be all anal about testing for NO3 and poor with CO2 and that will cause many more issues for you.

I'm not telling you this to confuse you. I'm just saying "test the water" is not as simple as many make it sound.

There are often a couple of things going on, testing good CO2 levels is not easy, no nutrient issue will work if that's messed up.

You can add nutrients 3 x a week(same amounts) and have the same result and not every other day. You can also add perhaps 1/2 the volume and have similar results.

Go conservative at first and watch the plants and their response to nutrients.
Then add more, but add one at a time and see.

Watch the plants, they never lie.
That will get you farther than test kits will.

There's is considerable doubt, to the point of not even bothering to test for traces with an Iron test kit. Try it sometime and see for yourself.
Test at dosing time, 15 min 1 hr, 4 hr and 12 hr.

If I'm not going to test for those, I need another way to assure the plants have enough, I really do not know what too much traces are.

Beyond any positive improvement by adding more seems to be a good enough range to me at high light and non limiting conditions for NO3/PO4/GH/CO2 and light.

Anything less than this, will not have as much demand.
Excess is not going to cause a problem unless very very very high and out of the ranges of most screw ups and over dosings.

The range for good plant growth is very wide as long as there is enough.

Regards,
Tom Barr

sawallace · Mar 19, 2005

Re: EI testing strategies

Thanks for the reply Tom,
I actually have readings of around 80ppm NO3 and 3-5ppm PO4. They are from "cheaper" kits, AP to be exact. Nonetheless, I find it necessary to test because I don't have a local water report that tells me anything, it just gives me a HUGE range. I have done the test calibrations, everything seems reasonable. Algae is minimal, except for some spot algae. Plants seem fine, it's the fish I'm worried about.

I test to get a feel for things. I do not have as much experience as you do, so I'm "feeling" my way through with the aid of test kits. I know accuracy is a concern, but it's all I have.

aquabillpers · Mar 20, 2005

Re: EI testing strategies

The several NO3 test kits that I tested all produced the same ballpark results up to about 20 ppm, but they were all over the place above that. API is as good as any, plus it provides good arm excercise from the required heavy shaking.

Bill

sawallace · Mar 20, 2005

Re: EI testing strategies

I'm not too concerned about the test, I am trying to figure out a strategy that most could apply to determine if what they are dosing is right.

My ultimate goal is NOT to test as often as I have. I made an error and went by other people's regimens, which will not work with my tank/tap. I'm not looking for the easy answer, for example "add X amount of this or that." What I'm interested in is HOW to figure out what amounts to dose.

What I'm looking for is, for those of us who cannot simply look and tell what's in excess or deficient, is a method to test and figure out what needs to be done to ensure long tem success.

What I'm interested in is HOW to figure out what amounts to dose. Maybe I'm putting too much effort into this It's only my second week. Like I said above, I made an error and dosed some other's amounts. Perhaps things will fall into place with experience.

defdac · Mar 21, 2005

Re: EI testing strategies

Make a really big water change (you know your water parameters, right?) and then add 10 ppm NO3 and 1 ppm PO4.

Now that is the levels you will have and these *inorganic* levels will dive if all params are right due to massive plant uptake. When the plants stop pearling do another full dose of everything.

Organic NO3 and PO4 levels, not usable by plants, might go up from fish poop, but not high enough in a week until next big water change where you sweep down every level to tap-water-levels.

Skip the test kits.

Laith · Mar 21, 2005

Re: EI testing strategies

Oh that is interesting. I had heard that there was a difference between organic and inorganic but hadn't really figured out the impact.

So you're saying that test kits measure both organic and inorganic and that if the kit is saying your have 40mg/l of NO3 this could be NO3 that's unusable by plants?

fishface · Mar 21, 2005

Re: EI testing strategies

so in nature, who's adding the inorganic p04 and no3? organic must work or there would be no plants anyhwhere except in our tanks. or are there other sources of inorganic that i don't know about??

Ian H · Mar 21, 2005

Re: EI testing strategies

Organic, inorganic NO3...............Have I missed something here? Can plants differentiate? Allbeit naive I'd have thought NO3 is just NO3 to a plant and as long as it's not bound to a complex molecule it is used as a source of nitrogen by the plants. To me it's just chemicals is it to the plants?

I'm not saying you're wrong, you understand but I am querying it all the same.

Ian

defdac · Mar 21, 2005

Re: EI testing strategies

In nature, and in the aquarium, the organic bound minerals get mineralized by microbes in the substrate - but how fast and how much noone knows. It will probably go up and down, making the growth jumpy with periods of less growth.

EI will remove this uncertaintanty from the equation due to the large water changes with fresh inorganic levels that are easy for the plants to assimilate through shoots and leaves.

I found a thesis made here in my home town about mineralization rates for those who want to dive into details:
http://www.ep.liu.se/exjobb/ituf/2004/mv-d/001/exjobb.pdf
"Mineralization Rates of Organic Matter in Freshwater Sediments when Different Electron Acceptors Dominate"

defdac · Mar 21, 2005

Re: EI testing strategies

.. if you have quite high no3-levels from fish poop and add KNO3 you will probably be able to measure an increase of the NO3-level and then the NO3-levels dive down:
http://fins.actwin.com/aquatic-plants/month.200501/msg00418.html

I venture to guess the cause for this.

More easily absorbable inorganic N from KNO3 will make the enzyme production and photosynthesis go up, with higher oxygen-levels in the substrate making the microbes work better/faster, and from the second Barr-report you all know Enzymes are like catalysts in the plants making the uptake/usage more efficient in the plant?

sawallace · Mar 21, 2005

Re: EI testing strategies

defdac said:

Make a really big water change (you know your water parameters, right?) and then add 10 ppm NO3 and 1 ppm PO4.
Click to expand...

That's what I did originally, except I also noticed that many others are adding 2+ppm of PO4 and a heck of alot of traces, which I followed. The problem with this is I already have high NO3 in my tap. If I continued to do 50% WC weekly, my NO3 could have killed my fish eventually.

I was thinking of possibly a simple solution like:

Goal - tap level + uptake rate / 3

If that formula is right (most likely not), you would have to know your uptake and the best level for your particular tank.

My concerns beyond this are:

-How the size of water changes affect levels (I'm chemisty challenged so I do not how to calculate what a WC will do to tank levels)

Laith · Mar 21, 2005

Re: EI testing strategies

sawallace said:

My concerns beyond this are:

-How the size of water changes affect levels (I'm chemisty challenged so I do not how to calculate what a WC will do to tank levels)
Click to expand...

As we're talking about concentrations here, this will be in direct proportion to the % water change . If you have 20mg/l NO3 in the tank before a water change and you do a 50% water change, you will end up with 10mg/l (assuming the water you add has no nitrates!). If you have 1mg/l of PO4 before, 50% water change will result in a PO4 concentration of 0.5mg/l (once again with the same assumption).

m lemay · Mar 21, 2005

Re: EI testing strategies

Laith said:

As we're talking about concentrations here, this will be in direct proportion to the % water change . If you have 20mg/l NO3 in the tank before a water change and you do a 50% water change, you will end up with 10mg/l (assuming the water you add has no nitrates!). If you have 1mg/l of PO4 before, 50% water change will result in a PO4 concentration of 0.5mg/l (once again with the same assumption).
Click to expand...

50% water change makes the math easy. If your tank has 10ppm nitrate and your tap has 5%, the tank will have an average of the 2 after the water change or 7.5ppm. Assuming a 50% water change the formula would look like this: (tank water ppm + tap water ppm) divided by 2= Water after water change ppm. This same formula can be used for phosphate also.

Marcel

Gill Man · Mar 22, 2005

Re: EI testing strategies

Since the topic is EI fertilization strategies, I'll throw this one out. I'm planning on NOT doing a water change today. I've done no testing since last week after my 75% water change, just been adding 3 ppm NO3, 3 ppm K2SO4, and 2 ppm PO4 every other day, and 10 ml of CSM+B and 30 ml Fourish Excel daily. CO2 is set around a calculated 47 ppm. Plants are growing in VERY lushly and algae is disappearing.

The reason for skipping a water change is that I want to see if I can maintain the nutrient target levels at the current dosing strategy as a test for when I take off for a long vacation next month. I'll test today and see where all the nutrient values are and make adjustments to this week's dosing if necessary. I plan on testing an automated system the following two weeks after next. I plan on mixing micros with macros in the same container but in more dilute concentrations than I normally use.

If all goes well, I may just keep the water change every two weeks method as well as the automated system.

defdac · Mar 22, 2005

Re: EI testing strategies

sawallace said:

The problem with this is I already have high NO3 in my tap. If I continued to do 50% WC weekly, my NO3 could have killed my fish eventually.
Click to expand...

No you wouldn't.

If you gain, let say 20 ppm NO3 from fish poo and your tap has 20 ppm NO3 and you have a 100 litres aquarium the total amount of NO3 in the aquarium is 4000 mg NO3 before wc.

A 50% wc will remove 2000 mg NO3 and 50 litres of 20 ppm NO3 tap-water will add 1000 mg NO3, rendering the aquarium water 30 ppm NO3.

Let's look what happens if you have no NO3-uptake at all from plants:

3000 mg + 2000 mg - 0,5*(3000+2000) mg + 50*20 mg = 3500 mg
3500 mg + 2000 mg - 0,5*(3500+2000) mg + 50*20 mg = 3750 mg
3750 mg + 2000 mg - 0,5*(3750+2000) mg + 50*20 mg = 3875 mg
3875 mg + 2000 mg - 0,5*(3875+2000) mg + 50*20 mg = 3937,5 mg
3937,5 3968,75
3968,75 3984,375
3984,375 3992,1875
3992,1875 3996,09375
3996,09375 3998,046875
3998,046875 3999,023438
3999,023438 3999,511719
3999,511719 3999,755859
3999,755859 3999,87793
3999,87793 3999,938965
3999,938965 3999,969482
3999,969482 3999,984741
3999,984741 3999,992371

.. so you will asymptotically go to 40 ppm in the worst case scenario where plant uptake is nil.

But plant uptake should be around 1-5 ppm a day, and with 2,5 ppm NO3-plant uptake a day (250 mg NO3 *7 per week):

3000 1750
1750 1125
1125 812,5
812,5 656,25
656,25 578,125
578,125 539,0625
539,0625 519,53125
519,53125 509,765625
509,765625 504,8828125
504,8828125 502,4414063
502,4414063 501,2207031
501,2207031 500,6103516
500,6103516 500,3051758
500,3051758 500,1525879
500,1525879 500,0762939
500,0762939 500,038147
500,038147 500,0190735

5 ppm NO3 that is.

No need to worry about the fish.

sawallace · Mar 22, 2005

Re: EI testing strategies

I wish i knew what all those numbers meant defdac

The way I figure it is:

My tap +- 20ppm NO3
If I added 10ppm (x3 per week) I would have 50ppm
Now for uptake. I don't have ANY stem plants, so this is low. I don't know exactly how much so lets just take the midpoint and say 2.5ppm/day
20+30-7(2.25)= 34.25 at the end of the week.

50% WC
(34.25 + 20)/2 = 27.125

So i gained 7.125ppm after the WC

Now, in subsequent weeks;
27+30-7(2.25)=41.25 at the end of week 2
50% WC;
(41.25 + 20)/2 = 30.625
Gained 3.5

30+30-7(2.25)=44.25 end of week 3
50% wc
(44.25 + 20)/2= 32.125
Gained 1.5ppm

(this math has always confused me, but it seems like you will have lower gains after each subsequent WC if everything remains constant. I have more confidence in EI now)

By doing the math, (if I calculated it right of course) it doesn't seem like i'm on the right path to 80ppm, however, this does not include fish waste NO3. Who knows how much that adds.

So, in conclusion, I don't know what the heck I'm doing wrong Perhaps something else was limiting NO3 uptake??? Or maybe a miscalculation by me?? Overfeeding?? Overcrowding?? Who knows...I was hoping to find out if there was a possibility of inflated test results due to the timing of my tests. Doesn't seem like that's the case.

Ian H · Mar 22, 2005

Re: EI testing strategies

Look guys this is getting far too complicated...............Too many numbers.

Sawallace, if your tapwater contains 20ppm NO3 I don't see why you need to add KNO3 at all, just add KCL or K2SO4 for the K.

The nitrates in my tap are currently close to zero, I do add KNO3 to bring it up to 20ppm. I only add KNO3 at the weekly water change to keep it at that level. I do have a lot of fast growing stem plants that need serious pruning at least once a week, so these do use the nitrates up, also I have a very heavily stocked tank.

Ian

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