EI and K2SO4 - The Planted Tank Forum
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post #1 of 12 (permalink) Old 12-11-2015, 10:31 PM Thread Starter
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EI and K2SO4

Newbie learning about EI dosing here.

So I know about, KNO3 KH2PO4

But on gla's EI fert package there is also K2SO4, do I add the same amount as KH2PO4

And what about MgSO4 (it come with the 2 dosing mixing bottles)

So for my 22G tank it would be, per week,

KNO3 1.3g x 3
KH2PO4 .36g x 3
MgSO4 .36g x 3 ???
Trace .29g x 3
MgSO4 ??
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post #2 of 12 (permalink) Old 12-11-2015, 11:10 PM
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K2SO4 provides potassium. What many people fail to see at first is that KNO3 provides a significant amount as well. A standard EI dose for potassium is 7.5 ppm. KNO3 provides 4.73 ppm. This is usually enough. However, the additional potassium does no harm and in some cases helps. So I would add it.

If you are just starting I would use a nutrient calculator. The numbers below are from my Windows version.

Here is a basic explanation of what EI is and how it works. This may help. https://www.plantedtank.net/forums/11...explained.html

Zorfox's Planted Tank Calculator

Here are the numbers for standard EI ...

KNO3 1.018421322 gm (approximately 1/4 teaspoons)

KH2PO4 155.13mg (approximately 1/32 teaspoons)

K2SO4 417.6 mg is approximately 1/16 teaspoons(s)

MgSO4.7H2O 4.22 gm (approximately 3/4 teaspoons)
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post #3 of 12 (permalink) Old 12-11-2015, 11:23 PM Thread Starter
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Quote:
Originally Posted by Zorfox View Post
K2SO4 provides potassium. What many people fail to see at first is that KNO3 provides a significant amount as well. A standard EI dose for potassium is 7.5 ppm. KNO3 provides 4.73 ppm. This is usually enough. However, the additional potassium does no harm and in some cases helps. So I would add it.

If you are just starting I would use a nutrient calculator. The numbers below are from my Windows version.

Here is a basic explanation of what EI is and how it works. This may help. https://www.plantedtank.net/forums/11...explained.html

Zorfox's Planted Tank Calculator

Here are the numbers for standard EI ...

KNO3 1.018421322 gm (approximately 1/4 teaspoons)

KH2PO4 155.13mg (approximately 1/32 teaspoons)

K2SO4 417.6 mg is approximately 1/16 teaspoons(s)

MgSO4.7H2O 4.22 gm (approximately 3/4 teaspoons)
Thanks

I saw your calculator. But I'm on a Mac >.<

Yet Another Nutrient Calculator
I tried using this one and got super confused

This one seems simple enough but only cover KNO3 and KH2PO4
https://www.thenutrientcompany.com/a...ei_calculator/
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post #4 of 12 (permalink) Old 12-11-2015, 11:43 PM
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Originally Posted by roostertech View Post
Thanks

I saw your calculator. But I'm on a Mac >.<
Gotcha. I'll be starting work on a new version to support Mac. However, it may be several months until complete.

The pen and paper still works.

Here is a formula,

Desired dose (ppm) * 100 / Percentage of fertilizer = milligrams / liter

So lets do your dose for K2SO4

Desired dose is 2.25 ppm since KNO3 provides a lot of potassium.

The percentage of fertilizer can be found by using a molar mass calculator. No worries. It's scarier than it sounds. Go here and enter K2SO4. You will see that K2SO4 is 44.8737 % potassium.

So....


2.25 * 100 = 225

225 / 44.8737 = 5.01

Now 5.01 is per liter....

22 gallons = 83.3 liters

So 5.01 * 83.3 = 417.3

That's all there is to it! Add 417.3 mg to your 22 gallon tank to raise K to 2.25 ppm. The same formula works for every dry fertilizer.
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post #5 of 12 (permalink) Old 12-12-2015, 12:04 AM Thread Starter
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Quote:
Originally Posted by Zorfox View Post
Gotcha. I'll be starting work on a new version to support Mac. However, it may be several months until complete.

The pen and paper still works.

Here is a formula,

Desired dose (ppm) * 100 / Percentage of fertilizer = milligrams / liter

So lets do your dose for K2SO4

Desired dose is 2.25 ppm since KNO3 provides a lot of potassium.

The percentage of fertilizer can be found by using a molar mass calculator. No worries. It's scarier than it sounds. Go here and enter K2SO4. You will see that K2SO4 is 44.8737 % potassium.

So....


2.25 * 100 = 225

225 / 44.8737 = 5.01

Now 5.01 is per liter....

22 gallons = 83.3 liters

So 5.01 * 83.3 = 417.3

That's all there is to it! Add 417.3 mg to your 22 gallon tank to raise K to 2.25 ppm. The same formula works for every dry fertilizer.
So if I repeat that for MgSO4

Target 10ppm
MgSO4 is ~20% Mg
10*100/20 = 50 per L
50 * 83.3 = 4165mg

But since my water is fairly hard, I probably should scale back lower Mg target?

The cloud is lifting, I'm getting this, I think lol.
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post #6 of 12 (permalink) Old 12-12-2015, 12:07 AM
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Fish food can also supply most nutrients, especially for a low tech tank. It is low in potassium and iron.
KNO3 is a reasonable source of potassium, but also provides nitrogen.
If your NO3 from fish food is already in the range you want, your plants will highly likely need a different source of potassium.
This is why K2SO4 is suggested for some tanks.

Magnesium may be needed, but I would look into it, first.

1) What is the GH of the tap water, and the tank? If the GH is over about 3 German degrees of hardness then the calcium and magnesium are likely in the right range for the plants. No need to add more.

2) If the GH is less than 3 degrees, then dose a more complete GH booster, which contains both calcium and magnesium in the right ratios. Plants use these minerals in a ratio something close to 4 parts Ca: 1 part Mg. The water does not have to have this exact ratio, but something close is a reasonable target.
If you are keeping hard water fish and need to raise the GH then use GH booster, not just magnesium.

3) If you suspect that the calcium and magnesium are not in a reasonable ratio, then test for calcium. Then make sure you get the correct formula to figure out how much magnesium there is. (it is not simply GH - Ca = Mg) Then you can dose whichever the tank needs in the right amount.
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post #7 of 12 (permalink) Old 12-12-2015, 12:18 AM
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Quote:
Originally Posted by roostertech View Post
So if I repeat that for MgSO4

Target 10ppm
MgSO4 is ~20% Mg
10*100/20 = 50 per L
50 * 83.3 = 4165mg

But since my water is fairly hard, I probably should scale back lower Mg target?

The cloud is lifting, I'm getting this, I think lol.
I hate to confuse you. Yes, your calculations are correct for MgSO4. However, GLA uses MgSO4.7H2O not plain MgSO4. MgSO4.7H2O (Epsom salt) is 9.8611% magnesium. Btw, you have to substitute * for a decimal on that website.

Also, you only need to dose about 5 ppm per dose.

As Diana pointed out fish food and tap water can play a large role. However, if you perform the 50% weekly water changes these variables can be ignored. That's one reason I like EI. It really is a very simple method as long as you do water changes!
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post #8 of 12 (permalink) Old 12-12-2015, 03:45 AM
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Quote:
Originally Posted by Diana View Post
3) If you suspect that the calcium and magnesium are not in a reasonable ratio, then test for calcium. Then make sure you get the correct formula to figure out how much magnesium there is. (it is not simply GH - Ca = Mg)
The conversion factors for Ca++ (calcium) and Mg++ (magnesium) to CaCO3 equivalents (GH) are 2.5 for Ca++ and 4.12 for Mg++.

So if you want to convert Ca++ to GH, you multiply the Ca++ reading by 2.5, and if you want to convert Mg++ to GH, you multiply the Mg++ reading by 4.12.

So if your GH reading is 107ppm (6 dGH), and your calcium test reads 30ppm Ca++, the conversion to GH would be (30 * 2.5) = 75ppm Ca++ as CaCO3 equivalent.

Total GH reading is 107ppm, so minus the Ca++ contribution to GH (107 - 75) = 32ppm CaCO3 equivalent Mg++.

Since 32ppm is the CaCO3 equivalent, we need to divide that by the Mg++ conversion factor (32 / 4.12) = 7.7ppm Mg++.

So you have 107ppm GH as CaCO3 equivalent, of which there is 30ppm Ca++ and 7.7ppm Mg++.

Feel free to edit.
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post #9 of 12 (permalink) Old 12-15-2015, 12:58 AM Thread Starter
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Quote:
Originally Posted by Diana View Post
Fish food can also supply most nutrients, especially for a low tech tank. It is low in potassium and iron.
KNO3 is a reasonable source of potassium, but also provides nitrogen.
If your NO3 from fish food is already in the range you want, your plants will highly likely need a different source of potassium.
This is why K2SO4 is suggested for some tanks.

Magnesium may be needed, but I would look into it, first.

1) What is the GH of the tap water, and the tank? If the GH is over about 3 German degrees of hardness then the calcium and magnesium are likely in the right range for the plants. No need to add more.

2) If the GH is less than 3 degrees, then dose a more complete GH booster, which contains both calcium and magnesium in the right ratios. Plants use these minerals in a ratio something close to 4 parts Ca: 1 part Mg. The water does not have to have this exact ratio, but something close is a reasonable target.
If you are keeping hard water fish and need to raise the GH then use GH booster, not just magnesium.

3) If you suspect that the calcium and magnesium are not in a reasonable ratio, then test for calcium. Then make sure you get the correct formula to figure out how much magnesium there is. (it is not simply GH - Ca = Mg) Then you can dose whichever the tank needs in the right amount.
Just got a GH/KH test kit.

So my tap water is GH 3, KH 2, so I guess I'll hold off on Mg for now.

I don't have a Ca test yet. Is the API liquid one good enough for this purpose?
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post #10 of 12 (permalink) Old 12-15-2015, 01:23 AM
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I've seen pretty reliable results with the API calcium test, but the resolution is low at 20ppm.

To increase resolution I add 60ml of sample water, 120 drops of Ca reagent #1, and then divide the number of drops it takes to turn the sample blue by 12. This increases the resolution to 1.66ppm.

I have a salifert Calcium test kit on the way, since this is stated as being for fresh and salt water, with a higher resolution from stock testing (5ppm). I'll be increasing the resolution of this test to around 0.5ppm.

Feel free to edit.
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post #11 of 12 (permalink) Old 12-15-2015, 01:59 AM
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http://www.ci.milpitas.ca.gov/_pdfs/...ity_report.pdf

Here is the water quality report for Milpitas CA. Looks like they have 2 sources. Which are you on? One has very soft water, small traces of Ca and Mg. If this is yours, I would add Seachem Equilibrium which supplies both Ca and Mg, unless you are keeping wild caught Discus, Angels or Cardinals, or similar demanding fish.

Adding just magnesium is not enough when there is so little of both Ca and Mg in the water.

Add enough Equilibrium to raise the GH by 1-2 degrees.
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post #12 of 12 (permalink) Old 12-15-2015, 02:21 AM Thread Starter
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Quote:
Originally Posted by Diana View Post
http://www.ci.milpitas.ca.gov/_pdfs/...ity_report.pdf

Here is the water quality report for Milpitas CA. Looks like they have 2 sources. Which are you on? One has very soft water, small traces of Ca and Mg. If this is yours, I would add Seachem Equilibrium which supplies both Ca and Mg, unless you are keeping wild caught Discus, Angels or Cardinals, or similar demanding fish.

Adding just magnesium is not enough when there is so little of both Ca and Mg in the water.

Add enough Equilibrium to raise the GH by 1-2 degrees.
Nice, I didn't even think about checking for water report.

I'm on the side supplied by SFPUC (the softer water of the two).

Avg 11ppm Ca, 3.9ppm Mg

Are there much difference between the GH+ products? I'm thinking about getting the Salty Shrimp one to use for my shrimp tanks.
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