Advice Please

Allwissend

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Short: ppm

Long:
mg/L describes the concentration obtained if you add X mg in a total volume of Y liters. As such it is easy to understand and apply it to make your own solution. It has the added advantage of using all standardized international units.

We can approximate 1L of water as having a mass of 1kg. 1kg=10^6 mg. Thus 1mg/1L ~~ 1mg/1kg~~1mg/10^6mg which is to say 1:10^6 by weight , or 1 part per million (ppm)

However, ppm(parts per million) is a ratio not a unit of measuring concentration. It is just like % or ‰. 10ppm can mean 10 µL/L or 10 grains of urea in 10^6 grains of CaCl2 or just 10 elephants to 10^6 giraffes.
 
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steve todd

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Short: ppm

Long:
mg/L describes the concentration obtained if you add X mg in a total volume of Y liters. As such it is easy to understand and apply it to make your own solution. It has the added advantage of using all standardized international units.

We can approximate 1L of water as having a mass of 1kg. 1kg=10^6 mg. Thus 1mg/1L ~~ 1mg/1kg~~1mg/10^6mg which is to say 1:10^6 by weight , or 1 part per million (ppm)

However, ppm(parts per million) is a ratio not a unit of measuring concentration. It is just like % or ‰. 10ppm can mean 10 µL/L or 10 grains of urea in 10^6 grains of CaCl2 or just 10 elephants to 10^6 giraffes.
 

Allwissend

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Yes, what Hoppy said is the answer. Just be aware that calculation will not give you the mass of the molecule rather the mass of the ion of interest.

For example for a K from K2SO4:

10mg/L K *670 L =6700 mg K

K in K2SO4 is 44.9% mass (from molar mass calculation)

6700/0.449=14922 mg K2SO4

Same can be done for Kno3 and KH2PO4
 

steve todd

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if i understand correctly i should add 10mg\L of NPK every W\C how about micro nutrients should i be adding them if so at what dose

cheers
 

Allwissend

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Huh, not sure everything is clear. Let us go step by step.

What source do you have for N P K and what for traces/micronutrients?
Are they powders or are you using a solution? If so which brand-product?
 
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Allwissend

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For a 150G aquarium

4.63g KNO3 will add 5mg/L NO3 and 3,15 mg /L K

0.78g Kh2PO4 will add 0.75mg/L PO4 and 0.6 mg/L K

40ml flourish trace will add 0.006 mg/L Mn and the rest

You also need a Fe source, better if you can find it as Fe-DTPA. Dose for 0.2 mg/L weekly.

This weekly dose should be enough to cover the needs of Anubias. I would suggesting dosing double the above the first week.
How high the values will accumulate in your tank depends on how often you change the water. 50% once a week will lead to max 2x the fertilizer dose per week. 50% once a month will lead to 8x the fertilizer dose per week.

If what NO3 is generated from fish leads to high NO3 values (40+), replace the KNO3 with K2SO4(by and large same dose)(completely or partially).

After 3 or so weeks you can try and reduce the doses and see what happens. If growth slows down or is deficient increase back up.

The dosing itself is a little light on traces, as Anubias sp. Are not demanding consumers. Nevertheless, break the weekly dose in 3-7 doses.

May be better to make 50x solutions. This help you be more accurate in weighting the ingredients and in dosing them. You can also easier adjust the dose. It is however not required for a large tank such as yours.
 

Allwissend

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Yeah sorry, I was on my mobile and spared some words :)

Say the weekly dose is 40mL. You can dose 8mL every day for 5 days, 2 days rest. Or you can add 15 ml on Monday and Wednesday, and another 10mL on Friday. I prefer daily use as it is easier to integrate in a routine.

By 50x, I mean a solution from which you can dose 50 times. To make it, for example:

Measure 4.63g KNO3 * 50 = 231.5g KNO3
Add water to make a total volume of 1L.

1L=1000mL=50*20mL

This means that you can add 20mL from the solution you just created and get the desired conc.. In other words, 20mL of this solution in 150G aquarium add 5mg/L NO3 and 3.15mg/L K

Regards
 

tiger15

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The dosing calculation requires math, unit conversion and understanding of stoichiometry, not easy to master unless one is a practicing scientist/engineer or fresh in college chemistry. You can avoid the confusion by using the Rotala calculator below, as someone knowledgeable in chemistry has worked out the formulas for you.

http://www.rotalabutterfly.com/

As Allwissend pointed out, ppm is just a ratio, which can be by weight, by volume or by unit. For example, 400 ppm of CO2 in the atmosphere is commonly referred to by volume, whereas 3 or 30 ppm CO2 in water is by weight, and the conversion is complex.
 

Allwissend

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Depends on the source. I think seachem trace does not have any iron. Do you use another source?

With solid Dtpa Fe 11%, you will need 1.03g to reach 0.2mg/L