po4 plant uptake?

blahblah said:

Hi to everyone on this forum. Could I touble somebody for answer to this, my first post.

I've been dosing Seachem phosphorus into my tank - I've only been adding ferts for 1.5 weeks, and the tank is only 3.5 weeks old - 2 days ago the phosphorus test was 0.5ppm. I wanted to get the levels a little higher, so dosed 50% more than normal on the same day as I did the test.

Today I tested again for PO4 today, same result, 0.5ppm.

I am guessing either the uptake for phosphorus is reasonably signifacant, or my test kit is not sensitive enough. I am using Hagen PO4 test kit.

I then added 10 drops of Seachem Phosphorus to the water sample post test, shook the test tube, and no difference! Is that a reasonable test for the sensitivity of the test kit? I read on here about the bucket test, should I do that instead?

What does anyone think about this? Maybe this is all normal, but I'm a definite newbie

, and would appreciate some input from the people who know

nitrate 40ppm btw

Thanks

Click to expand...

Hi, you need to be sure that your Test Kit is accurate by calibrating it. This is how you calibrate it. All credit to LeftC for posting this.

Here's a way to make 1.0, 2.0, 3.0, 4.0 and 5.0 ppm PO4 reference solutions:
Add 1.433 g of KH2PO4 to 1 L distilled or DI water. This makes a 1000 ppm PO4 solution. (It's really a 1000.09 ppm solution.)

Add 1 mL of the 1000 ppm solution to 9 mL of distilled or DI water. This makes 10 mL of a 100 ppm PO4 solution.

Add 2 mL of the 100 ppm solution to 18 mL of distilled or DI water. This makes 20 mL of a 10 ppm PO4 solution.

To make a 1.0 ppm PO4 solution:
Add 1 mL of the 10 ppm solution to 9 mL of distilled or DI water. This makes 10 mL of a 1.0 ppm PO4 solution.

To make a 2.0 ppm PO4 solution:
Add 2 mL of the 10 ppm solution to 8 mL of distilled or DI water. This makes 10 mL of a 2.0 ppm PO4 solution.

To make a 3.0 ppm PO4 solution:
Add 3 mL of the 10 ppm solution to 7 mL of distilled or DI water. This makes 10 mL of a 3.0 ppm PO4 solution.

To make a 4.0 ppm PO4 solution:
Add 4 mL of the 10 ppm solution to 6 mL of distilled or DI water. This makes 10 mL of a 4.0 ppm PO4 solution.

To make a 5.0 ppm PO4 solution:
Add 5 mL of the 10 ppm solution to 5 mL of distilled or DI water. This makes 10 mL of a 5.0 ppm PO4 solution.
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I changed the first step in both reference solutions. If you have scales that can go to 3 places; you're OK. If you have scales that will meaure to one decimal place or no decimal place; you can use the other first step.

How to Make Reference NO3 and PO4 Solutions II

Here's a way to make 10, 20, 30, 40 and 50 ppm NO3 reference solutions:

Note - This step requires that you have scales that can measure to 3 or more places. Add 1.631 grams of KNO3 to 1 L distilled or DI water. This makes a 1000 ppm NO3 solution. (It's really a 1000.29 ppm NO3 solution.)

If you have scales that measure to no decimal place or one decimal place in grams; here’s two options. Omit the above step and start here:Add
Add 5 grams to 3065 mL or 10.0 grams of KNO3 to 6.13 L of distilled or DI water. This makes the 1000 ppm NO3 solution. (It’s really a 1000.49 ppm NO3 solution.)

Add 2 mL of the 1000 ppm solution to 18 mL of distilled or DI water. This makes 20 mL of a 100 ppm NO3 solution.

Add 15 mL of the 100 ppm solution to 15 mL of distilled or DI water. This makes 30 mL of a 50 ppm NO3 solution. You can use this for the 50 ppm NO3 reference solution.

To make a 10 ppm NO3 solution:
Add 2 mL of the 50 ppm solution to 8 mL of distilled or DI water. This makes 10 mL of a 10 ppm NO3 solution.

To make a 20 ppm NO3 solution:
Add 4 mL of the 50 ppm solution to 6 mL of distilled or DI water. This makes 10 mL of a 20 ppm NO3 solution.

To make a 30 ppm NO3 solution:
Add 6 mL of the 50 ppm solution to 4 mL of distilled or DI water. This makes 10 mL of a 30 ppm NO3 solution.

To make a 40 ppm NO3 solution:
Add 8 mL of the 50 ppm solution to 2 mL of distilled or DI water. This makes 10 mL of a 40 ppm NO3 solution.




Here's a way to make 0.1, 0.2, 0.5, 1.0, 2.0, 3.0, 4.0 and 5.0 ppm PO4 reference solutions:

Note - This step requires that you have scales that can measure to 3 or more places. Add 1.433 g of KH2PO4 to 1 L of distilled or DI water. This makes the 1000 ppm PO4 solution. (It's really a 1000.09 ppm solution PO4.)

If you have scales that measure to no decimal place or one decimal place in grams; here’s two options. Omit the above step and start here:
Add 5.0 grams of KH2PO4 to 3.49 L of distilled or DI water or 2.5 grams of KH2PO4 to 1745 mL of distilled or DI water. This makes the 1000 ppm PO4 solution. (It’s really a 999.86 ppm PO4 solution.)

Add 1 mL of the 1000 ppm solution to 9 mL of distilled or DI water. This makes 10 mL of a 100 ppm PO4 solution.

Add 2 mL of the 100 ppm solution to 18 mL of distilled or DI water. This makes 20 mL of a 10 ppm PO4 solution.

To make a 0.1 ppm PO4 solution:
Add 1 mL of the 10 ppm solution to 99 mL of distilled or DI water. This makes 100 mL of a 0.1 ppm PO4 solution.

To make a 0.2 ppm PO4 solution:
Add 1 mL of the 10 ppm solution to 49 mL of distilled or DI water. This makes 50 mL of a 0.2 ppm PO4 solution.

To make a 0.5 ppm PO4 solution:
Add 1 mL of the 10 ppm solution to 19 mL of distilled or DI water. This makes 20 mL of a 0.5 ppm PO4 solution.

To make a 1.0 ppm PO4 solution:
Add 1 mL of the 10 ppm solution to 9 mL of distilled or DI water. This makes 10 mL of a 1.0 ppm PO4 solution.

To make a 2.0 ppm PO4 solution:
Add 2 mL of the 10 ppm solution to 8 mL of distilled or DI water. This makes 10 mL of a 2.0 ppm PO4 solution.

To make a 3.0 ppm PO4 solution:
Add 3 mL of the 10 ppm solution to 7 mL of distilled or DI water. This makes 10 mL of a 3.0 ppm PO4 solution.

To make a 4.0 ppm PO4 solution:
Add 4 mL of the 10 ppm solution to 6 mL of distilled or DI water. This makes 10 mL of a 4.0 ppm PO4 solution.

To make a 5.0 ppm PO4 solution:
Add 5 mL of the 10 ppm solution to 5 mL of distilled or DI water. This makes 10 mL of a 5.0 ppm PO4 solution.