# Dosing KCl, please review my math!



## solarz (Aug 31, 2010)

Hi all, I just picked up a box of Muriate of Potash (KCl) 0-0-60 yesterday, and I'm trying to calculate the dosage. Please review my calculations and let me know if you find any problems!

(I'm copying numbers from an excel sheet, so there might be small rounding errors.)

*Constants*

3.7854 L/gal
52.4% mass of K in KCl
20 mg/L or ppm of K - target
6 g/tsp for KCl

*Initial Dose*

Tank Volume: 20 gallons, or *75.7 L*

75.7 L * 20 mg/L = 1514 mg of K (target) = *1.514 g of K (target)*
1.514 g / 52.4% = 2.8896 g of KCl ~= *1/2 tsp of KCl* over 1 week

*Water Change*

WC Volume: ~5 gallons, or *18.9 L*

18.9 L * 20 mg/L / 1000 / 52.4% = 0.722 g of KCl, or ~ *1/8 tsp of KCl* per water change.

Is this correct? Should I be taking into account the "0-0-60" in my calculation?

Is my water change dosage correct, or should I be taking into account plant consumption of K?

I am going to mix that amount of KCl into 300ml of water, and pouring 1/3 of it into the aquarium every 2 days. Is this a good procedure?

Thanks!


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## Darkblade48 (Jan 28, 2008)

Technically, you need to take into consideration the amount your plants will consume, which can vary.

I would just stick to EI dosing; you cannot really overdose on potassium, because at that point, you will have other problems (i.e. osmolarity).


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