EI dosing calculator - are UKAPS guidelines inconsistent?

[greenink]

[edit - simple EI calculator is at the bottom of this post]

Having trouble with various versions of the 'right' EI dose. Seems to me the UKAPS EI guidelines on ppm and teaspoons are inconsistent and also don't match the Aquarium Plant Foods ones - so which is right?

Have used the ppm calculator on James' Planted Tank to work out the ppm impact of the recommended UKAPS teaspoon dose. The UKAPS recommendation for ppm is:

Nitrate (NO3) 20ppm per week
Potassium (K) 30ppm per week
Phosphate (PO4) 3ppm per week
Magnesium (Mg) 10ppm per week
Iron (Fe) 0.5ppm per week

And the recommended solution guidelines (in the same article) are:

NPK (Nitrogen + Phosphorus + Potassium) Mixture for 20 Gallon Tank [75.7 liters]
1 month = 4 Weeks
3 doses of NPK per week
Therefore there are 12 doses of NPK per month
Multiply a single dose teaspoon value by 12 => [3/16 tsp KNO3]*12 = 2 ¼ tsp KNO3
[1/16 tsp KH2PO4]*12 = ¾ tsp KH2PO4
[1/2 tsp MgSO4]*12 = 6 tsp MgSO4
Add these to 600ml of tap or distilled water

Now this mixture must serve 12 doses so each dose is 600ml/12 = 50ml

Putting this into the calculator on James' Planted Tank gives you these results:

Which is inconsistent with the ppm dosing. By my calculations you need to add a lot more chemicals:

So:

1. Have I got something wrong in my calculations (have triple checked!)
2. Is the UKAPS guidance inconsistent? If so, which is right - teaspoons or ppm?
3. Is James Planted Tank wrong?

Here's a link to the excel spreadsheet I made to do this. (The Macros are safe - I made it on a mac with no virus' - they just do conditional colour formatting to make warnings clearer). The top calculator will give you an easy way of calculating an EI mix for any tank size, with any solution combination, and tell you whether the solution is too concentrated to dissolve properly - to meet the same standards as the UKAPS teaspoon guidance. The bottom calculator does the same thing for the UKAPS ppm guidance. I can't find a way of making the two consistent!

 

[Matt Warner]

Re: EI dosing calculator - are UKAPS guidelines inconsistent

Hi, who cares how much of which chemical gives a specific ppm. The whole idea of EI dosing is that it is meant to be simple. It doesn't matter if you add way too much fertiliser over a week which is the whole idea of it. All that will happen is that your plants will grow like crazy. Why over complicate things for yourself when as long as you are adding an unlimited amount of nutrients, you don't need to worry. EI is not an accurate dosing method you are estimating how much you need by giving the plants more than they can use so that they don't starve.

 

[greenink]

Re: EI dosing calculator - are UKAPS guidelines inconsistent

Yup take your overall point!

My issue is that the ppm numbers were what started the EI regime - and the UKAPS teaspoon measure solution appears to underplay these significantly. So under certain light conditions the plants would have deficiencies.

What led me to this is that the UKAPS measures are inconsistent with the Aquarium Plant Food measures (where lots of people buy their mix).

4tsp Potassium Nitrate
1tsp Potassium Phosphate
6tsp Magnesium Sulphate>
500ml water

Which gives you:

...so it's a lot 'weaker' in terms of what it adds to the tank than the UKAPS recommended dose. So was trying to work out which was right - and ppm seemed the safest comparison.

 

[Alastair]

Mikes got a fair point


Sent from my iPhone using Tapatalk

 

[Matt Warner]

Re: EI dosing calculator - are UKAPS guidelines inconsistent

Yeah I see what you mean now. The APF recipe is very lean on the nitrate. I add pretty much triple what that recipe says. I add around 2 tsp in 125l every week! I guess the recipe is just a guideline really. It's always better to start dosing heavy then lean it off if you need to.

 

[ceg4048]

Re: EI dosing calculator - are UKAPS guidelines inconsistent

Hello,
I don't understand why so many people want to turn something that was meant to be simple into rocket science. What does "right" mean? Do you imagine that everyone dosing EI should use exactly the same concentration levels? EI is a concept. It's a world view, not a formula. General guidelines regarding plant health are offered and it's up to the user to determine what adjustments need to be made based on the performance observed in the tank, and based on their objectives. People need to pick a recipe and get on with it. If an adjustment is necessary then it's OK, make the adjustment. You can adjust the dosing levels up to get higher growth rates - or to mitigate some deleterious factor in the tank (such as weak flow) or you can adjust downwards to reduce the growth rates and to reduce the maintenance requirements.

Some people prefer a leaner adjustment in order to lower the conductivity of the water for fish. If you're trying to breed soft water fish in a planted tank this is super important. It's so important that one may even accept the penalty of minor deficiency due to lean dosing if it achieves the breeding goals. If you're trying to meet a deadline for a scape to enter a competition however then you don't care about conductivity and you'll dump in massive amounts of PPM in order to maximize the growth rate. Does "right" or "wrong" have any relevance within this context?

The PPM used today may not be what you use a month from now, or a year from now. All we are trying to accomplish is to avoid nutrient deficiency. If this can be accomplished by having a lower PPM in one recipe versus another then bravo! If the estimated delivered PPM is off based on teaspoon values as opposed to using an electronic scale and stoichiometric analysis, well then just get over it and carry on. Do you see the images of the tank used in the EI tutorial? I did not use the PPM values listed in the tutorial. I used 3X the values because it was a huge tank with insufficient flow, and I'm always in a hurry. I did not really care about PPM, only in high performance. After the dust settled, I calculated what approximate PPM values were dosed so that I could later share the data with the nitrate haters, the phosphate haters, the ratio lovers and the PPM obsessed. Try to keep in mind that this is not Chemotherapy. We're just preparing a meal, that's all.

It's a waste of time comparing EI recipes, as discussed in the thread viewtopic.php?f=11&t=16457

Cheers,

 

[roadmaster]

Re: EI dosing calculator - are UKAPS guidelines inconsistent

Am new to wholesale planted tanks ,most of my previous expieriences with plant's were plant's in pot's placed in cichlid tank's where rooting them can become problematic, or in outdoor patio tubs and horse troughs.
I am thankful for those who post here and have learned much.
EI to me,is a way to see that plant's have more than they need in the way of nutrient's depending on ones application.
For me it is low tech tanks,No CO2 and scaled back dosing.
Could not begin to guess at how much I'm actually adding due to fish waste from fish load, Ton's (well maybe not ton's)of trumpet snails,fish foods.
Don't believe anybody could nail down exactly how much nutrient's they are adding with these factor's in mind and don't believe EI was meant to be strictly followed nor too preccise, Too many variables, Plant mass, slow grower's,fast grower's, Lighting type,intensity,duration,CO2 delivery.etc.
Is just a way to see that that plant's aren't lacking and adjusting the formula from there, depending on what the plant's tell me.(still working on this,learning)
I have quite a few fish, so KNO3 is not as much needed as perhaps some with fewer fishes.
Other's already have lots of N in tapwater supply.
I chose EI formula for my size tank, and dose maybe 25% of what those who do full EI in CO2 enriched tank's do.
I watch the plant's and adjust from there.
Beat's anything my previous effort's have produced with respect to growth even in my lowly low tech application.
PPM I'm actually adding,,I ain't got a clue, but the plant's and fishes are thriving so I ain't stressing.
Still watching plant's and trying to hear what they are saying.Still learning.

After re-reading above, me thinks I should clarify a little.
I know what I'm adding once a week or two with respect to KNO3,KH2PO4,trace but I'm alway's adjusting watching.

 

[greenink]

Grand. The Clive/Tom sulphur stew it is for me then.