dry fert dosage???

kooter

kooter

AquaMan
Dec 14, 2003
701
13
18
Mission, BC
something doesn't seem right?!:omg:
I just bought some No Salt (20% potassium) from the store. It is a 311g. container and it was close to $7.00.
According to Chuck's calculator, I would need to add 216g. (almost the whole container) to 250ml. of water to get the solution to 1ml. = 1ppm. raise in MY tank (120g. of water). Now, if this is right then I would need approx. 20ml. of this solution per week to bring the ppm to within the proper range.
So, 20ml. per week with a 250ml. solution = 12.5weeks or 3 months.
I thought the dry ferts would be cheaper?
I can get approx. 3 months out of my 500ml. Flourish Potassium and it is $7.99 per bottle.
???????? am I using Chuck's calculator wrong?? :huh:
 
Never tried Chucks calculator but the one I use doesn't have No salt as a choice.

I got a 1 lb bag of KNO3 and a 1 lb bag of K2SO4 from Rex for about 10.00 with shipping. They should last me about a year in my 75 gallon tank. So if you buy the RIGHT dry ferts its much cheaper.
 
yeh, I think I will order some. Thanks a ridiculous price for No Salt.
 
I think you might have misunderstood how to use Chuck's calculator. It calculates a dosage so that each millimeter of the solution increases the nutrient level by a predictable amount.

NoSalt is 100% Potassium Chloride (KCl), 20% K by volume.

According to chuck's calculator 12 tablespoons of KCl added to 250ml of solution will yield a 1ppm increase per milliliter dosed in 120 gallons of water.

Obviously you can't dissolve 3/4 cups of dry chemical in 250ml (or about one cup) of water, you'll just end up with mush. But the calculator doesn't care about things like that. You'll juave have to make those judgments yourself.

So you should either increase the amount of water or decrease the amount of dry fertilizer that makes up the solution. I'm certain that 3 tablespoons of KCl will dissolve completely in 250ml of water. This ratio will increase K by .25 ppm for each milliliter dosed in 120 gallons of water.

You might start with an initial dose to bring your Potassium up to the recommended 20ppm, which in this case is 80ml, then dose just a few ml per day to make up what the plants use. If over time you begin to see pinholes in leaves you know you need to increase your daily dosage.

-edit-

As for cost, dedicated dry fertilizers are sometimes cheaper but NoSalt is not exactly what I would consider expensive. Consider this..

There are 17.28 tablespoons to 311 grams of KCl. Let's say you dosed 5 ml of the 0.25ppm/ml solution per day which may or may not be necessary based on your plant's uptake. That's 288 doses, or 288 days for $8. Yeah dry ferts from Grigg or elsewhere may be a bit cheaper. But $8 for roughly 10 months of ferts isn't exactly what I would call expensive.

-edit again-

That said I do use dedicated dry ferts purchased from Greg Watson. The DIY methods work, but these are a little bit better.
http://www.aquariumfertilizer.com/
 
Last edited:
Quartermain said:
I think you might have misunderstood how to use Chuck's calculator. It calculates a dosage so that each millimeter of the solution increases the nutrient level by a predictable amount.

NoSalt is 100% Potassium Chloride (KCl), 20% K by volume.

According to chuck's calculator 12 tablespoons of KCl added to 250ml of solution will yield a 1ppm increase per milliliter dosed in 120 gallons of water.

Obviously you can't dissolve 3/4 cups of dry chemical in 250ml (or about one cup) of water, you'll just end up with mush. But the calculator doesn't care about things like that. You'll juave have to make those judgments yourself.

So you should either increase the amount of water or decrease the amount of dry fertilizer that makes up the solution. I'm certain that 3 tablespoons of KCl will dissolve completely in 250ml of water. This ratio will increase K by .25 ppm for each milliliter dosed in 120 gallons of water.

You might start with an initial dose to bring your Potassium up to the recommended 20ppm, which in this case is 80ml, then dose just a few ml per day to make up what the plants use. If over time you begin to see pinholes in leaves you know you need to increase your daily dosage.

-edit-

As for cost, dedicated dry fertilizers are sometimes cheaper but NoSalt is not exactly what I would consider expensive. Consider this..

There are 17.28 tablespoons to 311 grams of KCl. Let's say you dosed 5 ml of the 0.25ppm/ml solution per day which may or may not be necessary based on your plant's uptake. That's 288 doses, or 288 days for $8. Yeah dry ferts from Grigg or elsewhere may be a bit cheaper. But $8 for roughly 10 months of ferts isn't exactly what I would call expensive.

-edit again-

That said I do use dedicated dry ferts purchased from Greg Watson. The DIY methods work, but these are a little bit better.
http://www.aquariumfertilizer.com/
Click to expand...


I thought I must of been reading something wrong. Thanks for the clarification. I will try the 3tbsp mixed with 250ml. of water and start there.
I'm trying to find some stump remover now.....arrggh, not as easy as I thought!
 
I was also going to ask about measuring the ppm of potassium in the tank?
Is there a way or do you just dose an approx. amount and wait for pinholes/yellowing, etc. and adjust accordingly?
 
You can make your own ferts?? I never knew that! How do you make your own ferts? Can someone give me a link on how to make your own ferts for a planted tank? Thanks!
 
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