Do I still need to dose Potassium? - The Planted Tank Forum
 
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post #1 of 14 (permalink) Old 02-28-2014, 06:54 AM Thread Starter
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Do I still need to dose Potassium?

My tap water has around 20 ppm nitrates ,and 3.5 ppm Potassium.
I believe I can get away without dosing N ,but what about K?
My tank is 10 gallon and I change about 25-30% water each week.

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post #2 of 14 (permalink) Old 02-28-2014, 02:53 PM
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Coppied from a recommended level list.
Strive for the following nutrient levels: N (10-20ppm), P (0.5-2ppm), K (10-20ppm), Ca (10-30ppm), Mg (2-5ppm), Fe (.1ppm).

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post #3 of 14 (permalink) Old 02-28-2014, 03:20 PM
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The question about what you need to dose requires that you first decide on how much light you want to use. The more light, the faster the plants try to grow and the more nutrients they need to do so. With low light you can often do without any dosing.

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post #4 of 14 (permalink) Old 02-28-2014, 05:17 PM Thread Starter
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Quote:
Originally Posted by Raymond S. View Post
Coppied from a recommended level list.
Strive for the following nutrient levels: N (10-20ppm), P (0.5-2ppm), K (10-20ppm), Ca (10-30ppm), Mg (2-5ppm), Fe (.1ppm).
Thanks Raymond! I knew I had read somewhere that K levels should be around 2 ppm.
My tap water has 3.5 ppm K ,according to the water company list.
I have around 30 liters of water column in my 10 gallon tank(40 L) ,plus substrate ,hardscape etc.I change around 10 liters a week(30%) ,so I am adding 35 mg K after each WC.(am I correct?)

I also use Ferropol(Fe ,K ,and micros) ,I dose around 4 ml a week - 1 ml every other day.


Ferropol contains:

0.349% Fe - what does this mean in ppm?
1.00% K2O - what does this mean in ppm?
0.168% MgO water-soluble
0.024 % Mn
0.0006% Mo
0.009% Zn
0.0002% Co
0.0001% Al
0.380% S
0.0001% J
0.0001% V
0.0009% Cu

From what I've read ,K deficiency can be recognized by the appearence of holes in the leaves ,so it cannot be mistaken for something else - or can it?

Final question: does overdosing Iron or K cause lock up for the assimilation of other nutrients?

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post #5 of 14 (permalink) Old 03-01-2014, 01:55 AM
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I don't think you have to worry about overdosing anything with what you are currently doing. What is your current lighting?

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post #6 of 14 (permalink) Old 03-01-2014, 04:12 AM
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That's two people who asked which lights you have and wouldn't if it weren't needed info to answer this with any degree of accuracy. Just a hint.
From what I've read it's hard to overdose K, but iron is different. You can overdose that one fairly easily so be conservative on it. As far as lock up, actually it's the other way around. One of the Macros(and I don't know which one) has been said that when it combines/w the iron it makes it harder for the plant to take it up.
For this reason people dose Micros and Macros on separate days and it's said to be OK that way.
You mentioned Ferropol and dosing K but the Ferropol has K in it also and so you are
dosing more than 35mg perweek. I use the EI dose calculator and actually asked other to suggest dosages for my nutrients and use only the ones listed on the calculator.
Between all that I have a list that I use each week but I use that part of the calculator which gives the doses in teaspoons so I don't know how to change over what you have to the teaspoons. A picture of the tank would be helpful to determine the plant density as in light med or heavy amounts. That along/w the light level is
what you need to get an idea of how much to dose, the higher amounts of plants/lights needing more.

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post #7 of 14 (permalink) Old 03-01-2014, 06:03 AM Thread Starter
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My apologies, guys ,I forgot to mention the most important thing in the scheme - lights.

I have one T8 tube ,18w ,6500k ,which sits at about 12 inches above the substrate ,no reflector.Tank is a 10 g ,custom , 30'' long ,8'' wide ,10 ''high.It is pretty densely planted ,mostly low light ,easy plants.

Sometimes I need to top off one or two liters ,during the week ,else the heater's thermostat would be above water.
For 10 gallon (30 L) ,Ferropol should be dosed around 4-5ml ,each week ,according to the label.I have about 30 liters of water column ,and I dose 1 ml every other day ,during the week ,not sure if it makes a difference than dosing the entire weekly amount at once.
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post #8 of 14 (permalink) Old 03-01-2014, 06:04 AM
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Quote:
Originally Posted by Raymond S. View Post
As far as lock up, actually it's the other way around. One of the Macros(and I don't know which one) has been said that when it combines/w the iron it makes it harder for the plant to take it up.
When ferrous ions react with phosphoate anions, ferric phosphate precipitates out of solution, which is not usable by plants.

Anthony


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post #9 of 14 (permalink) Old 03-01-2014, 06:14 AM Thread Starter
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Quote:
Originally Posted by Darkblade48 View Post
When ferrous ions react with phosphoate anions, ferric phosphate precipitates out of solution, which is not usable by plants.
So it's the P which reacts with micros ,and that's the reason why they are dosed in separate days.Now I get it ,thanx.Ferropol doesn't contain any nitrates or phosphates ,according to the label.

Just performed a PO4 test ,it came out lower than 0.2 ppm.

Checked my water supply chart - P is lower than 0.1 in my tapwater.

Most ferts ,like my Ferropol ,and the majority of fish foods nowadays ,are said not to contain any phosphates or nitrates - I think I'm on to something here.
P may be the limiter in my tank ,when I had my light really close to the surface - algae bloom.
Maybe I should start dosing K2PO4 ,instead of Ferropol ,and dose the micros in a different day ,some Fe+traces ,with no added K.What do you guys think?
Can we buy K2PO4 in pharmacies ,or only in aqua-shops?

Can't come to work today ,Boss......I've got Bolbitis...

Last edited by Darkblade48; 03-01-2014 at 08:55 AM. Reason: Please use the edit function for back to back posts to keep threads cleaner
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post #10 of 14 (permalink) Old 03-01-2014, 08:04 AM
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KH2PO4 is on common fert list. K2SO4 is also.
I don't recognize that one you listed.
http://aquariumfertilizer.com/index....ditU=1&Regit=2

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post #11 of 14 (permalink) Old 03-01-2014, 08:56 AM
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Quote:
Originally Posted by sleepswithdafishez View Post
Maybe I should start dosing K2PO4 ,instead of Ferropol ,and dose the micros in a different day ,some Fe+traces ,with no added K.What do you guys think?
Can we buy K2PO4 in pharmacies ,or only in aqua-shops?
K2PO4 is not a proper chemical formula; perhaps you meant KH2PO4? Or perhaps K3PO4?

You might be able to find potassium phosphate containing products at the pharmacy (sold as enemas), but it is rather expensive.

The cheapest solution is to buy the bulk chemical from an agricultural/hydroponic store.

Anthony


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post #12 of 14 (permalink) Old 03-01-2014, 05:06 PM Thread Starter
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Quote:
Originally Posted by Raymond S. View Post
KH2PO4 is on common fert list. K2SO4 is also.
I don't recognize that one you listed.
http://aquariumfertilizer.com/index....ditU=1&Regit=2
Sorry ,I was about to go to work and I missed the "H" .
And thank you for the link !!

Quote:
Originally Posted by Darkblade48 View Post
K2PO4 is not a proper chemical formula; perhaps you meant KH2PO4? Or perhaps K3PO4?

You might be able to find potassium phosphate containing products at the pharmacy (sold as enemas), but it is rather expensive.

The cheapest solution is to buy the bulk chemical from an agricultural/hydroponic store.
Yes ,I was in a hurry and I skipped the H.I meant K2HPO4.
What is the difference between K2HPO4 and K3PO4 ,fert wise? Would the latter be more effective/less costly?

Can't come to work today ,Boss......I've got Bolbitis...

Last edited by Darkblade48; 03-01-2014 at 06:41 PM. Reason: Please use the edit function for back to back posts to keep threads cleaner
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post #13 of 14 (permalink) Old 03-01-2014, 06:44 PM
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Quote:
Originally Posted by sleepswithdafishez View Post
What is the difference between K2HPO4 and K3PO4 ,fert wise? Would the latter be more effective/less costly?
They are two different chemicals.

One has more potassium than the other, as indicated in the chemical formula.

The latter would contain more potassium. However, I do not see it commonly sold, so you may have to end up using the former.

Anthony


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post #14 of 14 (permalink) Old 03-01-2014, 08:56 PM Thread Starter
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Quote:
Originally Posted by sleepswithdafishez View Post
So it's the P which reacts with micros ,and that's the reason why they are dosed in separate days.Now I get it ,thanx.Ferropol doesn't contain any nitrates or phosphates ,according to the label.

Just performed a PO4 test ,it came out lower than 0.2 ppm.

Checked my water supply chart - P is lower than 0.1 in my tapwater.

Most ferts ,like my Ferropol ,and the majority of fish foods nowadays ,are said not to contain any phosphates or nitrates - I think I'm on to something here.
P may be the limiter in my tank ,when I had my light really close to the surface - algae bloom.
Maybe I should start dosing K2PO4 ,instead of Ferropol ,and dose the micros in a different day ,some Fe+traces ,with no added K.What do you guys think?
Can we buy K2PO4 in pharmacies ,or only in aqua-shops?
To quote myself ,I just read that we can only measure the amount of in-organic phosphates with the test kits ,thus only the level of phosphates which were broken down from the initial organic state - and made available for the plants.
So ,in the end ,maybe I have a decent phosphate level after all ?
I have 3 Peacock gudgeons ,3 amanos ,30-something Red Cherry ,one Oto ,and one Giant African shrimp ,in my 10 g.
I feed once or twice a day max(the fish) ,and leaving the crumbles which fall on the bottom - to shrimp.I throw some JBL shrimp balls every once in a while.
I may might as well have plenty of organic phosphates which are decomposed ,yet immediately consumed afterwards ,so nothing left to measure.
The more I read ,the more I enjoy this hobby!

Can't come to work today ,Boss......I've got Bolbitis...
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