# [Wet Thumb Forum]-How should I be dosing my fertilizer?



## Jeremy S (Apr 9, 2006)

I am going to be using K2SO4 as an example but I was wondering about this with all the other fertilizers as well. Since the target level of K is around 20 ppm are you supposed to dose enough K right after you do a water change to equal 20 ppm and then dose small amounts each day during the week to equal the amount that the plants take up? Or should you dose 2.8 ppm every day of the week to eventually add up to 20 ppm at the end of the week before you do a water change? Thanks.


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## Jeremy S (Apr 9, 2006)

I am going to be using K2SO4 as an example but I was wondering about this with all the other fertilizers as well. Since the target level of K is around 20 ppm are you supposed to dose enough K right after you do a water change to equal 20 ppm and then dose small amounts each day during the week to equal the amount that the plants take up? Or should you dose 2.8 ppm every day of the week to eventually add up to 20 ppm at the end of the week before you do a water change? Thanks.


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## George Willms (Jul 28, 2004)

Personally I dose potassium daily. I don't generally measure it directly, I just eyeball the amount I'm putting in. Squeeze, squeeze, enough!









George

Tank specs in profile


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## Justin Fournier (Jan 27, 2004)

I second George's method. I am currently using Seachems Potassium but have K2S04. Basically every second day I pour a good amount from the bottle. I am not sure how much, but it's a fair bit. about 1.5-2seconds worth of pouring.


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## perrush (Feb 24, 2003)

george and justin :

*ofcours* this isn't the best, maybe even not a good, way to do. You'll never sure the K you put in is used. Therefor it's pssible that you build up your K concentration.

I'll do it an other way.

Let's say you want to allow a maximum of 35 ppm. Then add K2SO4 to the water which you use to do the waterchances until 35 ppm K. Because you'll refill with water of 35 ppm, your actual K level will be (much) lower.

If you do a 30% W/C, your minimum level is almost 12 ppm (35/3) (if K was totally depleted before the W/C), maximum is 35 ppm (if no K was used at all)

Instead of putting it in all at once, you can spread it over as many portions if you like.

This way would prevent a build up of any nutrient.

--
English isn't my native language, but I guess you already noticed that ))
--

Perrush


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## gpodio (Feb 4, 2004)

I do bring levels back up to target following a water change, I don't test for anything besides nitrates, just use the doses that I have found to work best over time. I also prepare a mix of "a little of everything" each month and use an Eheim Liquidoser to add this mix on a daily basis. I dose a little more than I probably need to but I have found that I have better results this way. The only things I now keep an eye on are nitrates by way of test kit and iron by way of too much dust algae on the glass when levels are too high. The rest I just keep an eye on the plants to tell me if anything is missing. I do large weekly water changes to avoid any buildup over time. The automatic doser is a great help in my opinion, I refill it every week during water changes and I don't have to worry about dosing through the week. Before that I was dosing twice a week, sometimes 3 times.

Giancarlo Podio


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## Dr.T. (Jul 23, 2003)

I like the way you think, Perrush

Jeff (Dr.T.)
---------------------------
Tank info in profile
29 gallon tank
65 gallon tank


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## perrush (Feb 24, 2003)

> quote:
> 
> Originally posted by Dr.T.:
> I like the way you think, Perrush


Tnx T, I'm sure it's not perfect, but it's better than just dosing on sight.

Problem ... determing maximum and minimum levels.

But it's a fairly goof point to start from. Ofcours, W/C are crucial with this method

--
English isn't my native language, but I guess you already noticed that ))
--

Perrush


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## ScottH. (May 13, 2004)

I dose about two to three times a week. I think I may want to invest in one of those automatic dosers so I don't have to remember to dose all the time. That way I will just have to refill it once a week.

My goal is a sea of green.


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## ckll (Jun 20, 2003)

I'm thinking along Giancarlo's "I also prepare a mix of 'a little of everything' each month". In fact, I'm thinking of mixing my K2SO4, KNO3 and KH2PO4 into one stock and dose all in one shot.

Is this okay ? Will the chemicals react ? 

I know this limits my dosing amount in the sense that it will be "fixed" dosing, but that's what I'm doing anyway: adding powder to tank during w/c and midweek.


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## perrush (Feb 24, 2003)

@ ckll :

those three shouldn't be a problem

--
English isn't my native language, but I guess you already noticed that ))
--

Perrush


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## ckll (Jun 20, 2003)

Thanks!


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## sm (Apr 28, 2003)

would someone show me the photo of automatic doser?thanks


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## Guest (Sep 13, 2003)

> quote:
> 
> Originally posted by sm:
> would someone show me the photo of automatic doser?thanks


taken from http://www.bigalsonline.com

_The Eheim automatic fertilizing unit can be relied on to handle this task for you. Its dosage quantity can be accurately programmed simply by making the requisite number of turns, as can the daily identical dosing times. The unit is battery operated and can be placed wherever you like, on or near the aquarium hood. The electronic programming control is for daily precise dosage, suitable for the actual size of your aquarium. It has an option of manual release button operation and a visible filling level thru a transparent supply reservoir. Two-stage battery alarm with safety shutdown, LCD programming display and clock time. 
Price: $39.99_


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## sm (Apr 28, 2003)

Thank you for your valuable information


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