# How to dose K2SO4



## Anafranil (Mar 15, 2005)

I recently added K+ in the form of K2so4 with significant difference in the consumpion of the rest of the nutrients.I'd like some suggestions on how to dose for the following days until I find a chance to study EI.Also I'd like to know your average consumption of K+ in ppm weekly or daily.

Thanks


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## Salt (Apr 5, 2005)

How are you testing for K?

I use the Lamotte Potassium kit. I dose to 20 ppm after each weekly water change. K consumption is about 5-6 ppm per week. This can be replaced by dosing Seachem Potassium at the recommended dosage rate three times per week.

The numbers for dosing K2SO4 are:

0.0084357 grams raises K by 1 ppm in 1 gallon of water.

Example - 40 gallon tank raised from 0 to 20 ppm - 0.0084357 * 40 * 20 = 6.75 grams K2SO4.


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## Edward (May 25, 2004)

Hi
How to dose K? 
We have two choices; one is to use EI where chemicals are dosed dry in rough estimated levels often overdosed. The main ingredient is KNO3 where is enough K due to the overdose & flush practice. 
The other method is PPS where we never have to worry about K levels again. They are locked into defined solutions called SS, PF and NF. 

Thank you
Edward


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## plantbrain (Jan 23, 2004)

I have never worried about K+ is 15 years using EI............
I've also isolated and tested specifically for K+.
I've also done that for many years with ~300 species of aquatic plants and put many myths surrrounding K+ to rest.

Salt's ppm uptake is about what I find, roughly a 4:1 N:K although there is variation, plant to plant, tank to tank, research on aquatic plant, research on aquatic macrophyte dry weights, this is a rough good estimate.
N:K ratios of 1:1 seem best IME as far as a level in a tank. I've found lots of plant data specifically on aquatic plants that show this. 

Plants are far from requiring precise amounts and constituents, that's why EI works, and PPS, non CO2, PMDD and there is nothing wrong with "overdosing", everyone does it to a certain degree, PPS or otherwise........otherwise you run a limited tank and that tends to favor algae.......PO4 limitation methods showed this in year's past as well as poorer growth.....

K+ being locked at ppm range may sound nice, but offers no practical advantage in terms of horticulture.

I know this and can easily say this since I've actually tested this notion as many others have for well over 10 years. New folks might not know that, but there it is. 

See APD past postings for more references than you can shake a stick at as well as SFBAAPS member's tanks going for a decade.

As long as there is no limitation, K+ can be 5ppm or 50ppm or a 100ppm.
It did not influence plant growth unless limited.
No water changes will work quite sometime with EI also, build up may occur but EI can easily target an individual tank's needs by simply lowering the max dosing amounts till the plants show a negative response, you bump up the dosing when this occurs a tad higher and you are set. This is very easy and adds no more than is needed. 

It also relies on the plants rather than the added stage of using using a test kit or monitoring ppm ranges. That adds another stage of testing and then uses that information to monitor the plants. I'd rather spend time looking at plants than testing. Folks only have so much time to play with the hobby. Some might enjoy testing, most want to grow plants IME. 

So I find no support either in terms of science, nor practical isolated testing for any advantage of maintaining a precise level of K+, nor Ca nor most of these nutrients, as long as they are in a "range", plant growth is fine and these ranges are quite wide.

Many folks seem to think that a static level is somehow advantagous to plants and while PPS soltuions do provide a measure of K+ stability, is this useful?

A fairly basic question since it's a main contention of PPS.
One I have not heard any response to.

Edward, if you have evidence to contrary, I'd like to hear it. Many folks for many years did not find support that a stable K+ level say out side + or minus 20ppm did anything siginificant, I did not in isolated cases over 50+ppm range. That's many years and many tanks and many people andm many species of plants.

Most recently K+ and Ammannia, Erik had 100ppm + of K+ in his tank, I isolated it and did well over 50ppm+. No issues. 

Regards, 
Tom Barr


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