# How to dose better?



## JustinKScott (Aug 1, 2011)

So I know there is a lot we can't test for, which is why the estimative index and other such method were invented.. But what can we test for?

I have discovered phosphate tests.
And we all know ammo, nitrite, ph, nitrate tests.
Of course co2 drop check and TDS meter... Although I can't really get anything useful from TDS.

I'd love to test for all macro nutrients. The phosphate test really opened my eyes to why I was having such trouble with some plants... I hadn't been dosing enough.

What other tests are available to take some of the guessing out of dosing?


----------



## Zapins (Jul 28, 2004)

You mentioned most of them. NPK are the main nutrients and we can test for N and P. Potassium is a notorously hard element to actually test, results aren't usually very accurate, although there are tests out there for this nutrient as well. I don't think it is very important to test for K anyway since you usually get enough K from the other fertilizers.

You can test for Ca, and for GH, and using a formula you can get the Mg level in the tank. These levels don't really make much of a difference unless you are reconstituting RO water so if you test these levels once you'll likely know what the values are for many months.

There are iron tests, but they aren't very accurate. And for the rest of the micro nutrients you can't really test for them, so you must guess when dosing.

You are doing well with the tests you have already. I wish we had more tests for the micros, or even better - electronic tests like a TDS meter.


----------



## countcoco (Dec 28, 2010)

JustinKScott said:


> So I know there is a lot we can't test for, which is why the estimative index and other such method were invented.. But what can we test for?
> 
> I have discovered phosphate tests.
> And we all know ammo, nitrite, ph, nitrate tests.
> ...


IME, the tds meter is the most accurate way to measure nutrient concentrations. Just establish what the reading is w/o dosing and then double check your dosing with the meter. For instance, if you're dosing 5 ppm NO3 and 5 ppm K, the reading should increase by approximately 10 ppm.

It's also the best indicator for determining when you need a water change.

Iron and PO4 tests are a waste imo. The seachem NO2/NO3 test kit is really good too.

You'll also want to test gH regularly.


----------



## Zapins (Jul 28, 2004)

The TDS meter won't tell you which nutrients were used though. It just tells you total dissolved solids, which includes waste products. I don't think it is very useful for dosing macros since you don't know what was used up or what was produced as waste by bacteria, you might use 20 ppm of nutrients, and the bacteria put out 20 ppm of waste, so you think you don't need to dose. Alternatively your plants might use 20 ppm and the bacteria put out 50 ppm waste, so your total goes up by 30. There is no dependable relationship using a TDS meter IMO. As an indicator for water changes, it might be a good indicator, especially if you take an initial reading (as you said). 

Hagen PO4 tests are pretty accurate, can't speak for the other brands.


----------



## JustinKScott (Aug 1, 2011)

What about API po4? Accurate enough?


----------



## Zapins (Jul 28, 2004)

I'm not sure, I've never tried API's PO4 test, maybe someone else can step in?


----------



## Marcio_Moraes (Apr 29, 2011)

Hi there! IMHO the API PO4 test is a bit difficult to read, i mean, the colours for 0.0ppm, 0.25ppm and 0.5ppm are very close. The NO3 API test for instance is quite easier to read.


----------



## OTPT (Sep 27, 2010)

JustinKScott said:


> What about API po4? Accurate enough?


I calibrated mine and found it's quite accurate out of the box.
I mean it's good as long as your testing range is 0.25 PPM and higher 
(0.25, 0.5 and 1 is very easy to tell).

Lower than that the color is hard to discern (0.25 and 0 look very close).


----------



## niko (Jan 28, 2004)

Also, since you are just starting in this hobby I guess, google for information on how the Japanese dose their tanks with dry fertliziers. Find out what tests they use, how many spoons of fertilizers they add on a daily basis and how they add them (at what time of the day). 

Also find out what concentrations of N, P, K, Fe/Traces, Mg, Ca they maintain. I bet they keep them pretty high. 

--Nikolay


----------

