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#### Akira

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I have mixed up some dry fertilizers(to liquid) to rex griggs specs. How often do I dose the liquid mix? every day?

#### wkndracer

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Basic dosing with his weights/volumes and the resulting PPM is listed on that site.
Stating the obvious all tanks are different and unless you dose EI and reset regularly watching the plants will factor into how much and often.
I used his basic guides starting out to good result.
HTH

#### DarkCobra

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Rex doesn't assume any particular dosing style on his liquid mix page. Assuming you want to dose EI-style, the basic dosing instructions are here:

http://www.plantedtank.net/forums/fertilizers-water-parameters/21944-_dosing-regimes_.html

But that's for dry ferts and larger tanks. So as Rex says in his gruff manner, here's where the basic math comes in.

If I recall correctly: You have a Fluval Flora, with 7.9G max capacity. Some of that is filled with substrate and driftwood, rather than water. You also have slower growing carpet plants, and plan to keep shrimp, which means we can afford to dose a bit lean. So, we'll take the 40-60G dosing recommendation and divide by 10, to give us dosage for a 4-6G tank:

0.05 Tsp-KN03 3x a week
0.0125 Tsp-KH2P04 3x a week
0.0125 Tsp-Trace (CSM+B) 3x a week

For the first one, you have 3 teaspoons of KNO3 dissolved in 250ml of water. How many doses is that in the bottle?

3 / 0.05 = 60 doses

And how many liquid ml is each dose?

250 / 60 = 4.166 ml per dose

But you may not have a ml measuring vial, so if not, type the following into Google:

"4.166 ml in teaspoons"

And it returns:

"4.16600 ml = 0.845215311 US teaspoons"

You should be able to determine correct dosage for KH2PO4 and CSM+B by applying the same steps. Try it. Post the result if you want and we'll proof it.

#### wkndracer

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haha the Grumpy Son lists what each ml of will impart (ppm) mostly in 20 gallon increments using his solutions. Then further recommends what levels to maintain. On his main site a weekly dosing schedule is indeed listed.

From the summary page;
Suggested nutrient levels are Nitrates 10-20ppm, Phosphates 1-2 ppm, Potassium 10-20 ppm, Iron 0.5-1.0 ppm.

and of course the fert page, its there;
http://www.rexgrigg.com/ferts.htm

I lived on that site my first few months tanking plants.

#### Akira

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Rex doesn't assume any particular dosing style on his liquid mix page. Assuming you want to dose EI-style, the basic dosing instructions are here:

http://www.plantedtank.net/forums/fertilizers-water-parameters/21944-_dosing-regimes_.html

But that's for dry ferts and larger tanks. So as Rex says in his gruff manner, here's where the basic math comes in.

If I recall correctly: You have a Fluval Flora, with 7.9G max capacity. Some of that is filled with substrate and driftwood, rather than water. You also have slower growing carpet plants, and plan to keep shrimp, which means we can afford to dose a bit lean. So, we'll take the 40-60G dosing recommendation and divide by 10, to give us dosage for a 4-6G tank:

0.05 Tsp-KN03 3x a week
0.0125 Tsp-KH2P04 3x a week
0.0125 Tsp-Trace (CSM+B) 3x a week

For the first one, you have 3 teaspoons of KNO3 dissolved in 250ml of water. How many doses is that in the bottle?

3 / 0.05 = 60 doses

And how many liquid ml is each dose?

250 / 60 = 4.166 ml per dose

But you may not have a ml measuring vial, so if not, type the following into Google:

"4.166 ml in teaspoons"

And it returns:

"4.16600 ml = 0.845215311 US teaspoons"

You should be able to determine correct dosage for KH2PO4 and CSM+B by applying the same steps. Try it. Post the result if you want and we'll proof it.
Is my math correct that I would doze KH2P04 and Plantex CSM+b will be 1.041ml??

and the 1/8th a teaspoon for k2so4

#### Akira

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I prefer liquid as I use a syringe to dose.

#### DarkCobra

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Is my math correct that I would doze KH2P04 and Plantex CSM+b will be 1.041ml??

and the 1/8th a teaspoon for k2so4
There is already enough potassium in both the nitrate and phosphate solutions for most tanks. So skip it unless you see signs of potassium deficiency; small pinholes in older leaves, bordered by yellow, that grow larger with time. It is to me the most easily recognizable deficiency.

Your calculation on the KH2PO4 appears to be 50% too low. Assuming you followed Rex's instructions, you have 1.5 tsp. of KH2PO4 in 250ml of water. The dry dosage I calculated for your tank is 0.0125 tsp, so number of doses is:

1.5 / 0.0125 = 120

And dosage amount in ml:

250 / 120 = 2.083

There are many ways to approach mixing and determining dosage for liquid solutions. I went through the math with you rather than a simplified method, because once you understand that, you can figure it out any way you like.

One thing you might notice is that all the dosages are exact multiples of each other:

CSM+B = 1.041ml
KH2PO4 = 2.083 (2x as much as CSM+B)
KNO3 = 4.166ml (4x as much as CSM+B)

I doubt that's a coincidence, but rather a peek into Rex's personal dosing preferences and calculation methods.

If you wanted, you could put half as much KH2PO4 in a bottle, and a quarter as much CSM+B, and then you'll be able to dose the same amount (4.166ml) for each solution. They'll also run out at about the same time. There's also no harm in rounding up to an even teaspoon (5ml) if that's more convenient than a ml syringe.

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