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Can I have a quick double check please

Joined
27 Oct 2009
Messages
2,919
Location
Cumbria
I'm usually a spoon man but I need to mix up a bottle of ferts for when I go away that can be dosed in increments of 10ml. Reason being my 9 y.o daughter will be tank sitting and on the pay roll to dose the tank before she goes to school. To keep things simple for her I have 250ml dosing bottles which when you squeeze fill up 10 ml at a time and I'm just going to use pottasium nitrate and pottasium sulphate. There's plenty of po4 in the tap water and I generally add in mid week a little. Magnesium I will also spoon in on water change day as my water is extremely soft. Based on a few searches E.I parameters are.....
CO2 range 25-35ppm
NO3 range 5-30ppm
K+ range 10-30ppm
PO4 range 1.0-3.0 ppm
Fe 0.2-0.5ppm or higher (?)
GH range 3 degrees ~ 50ppm or higher

Using James Calculator I have come up with this.

Based on dosing 3 times alternate days 20ml

25 grams kno3 in 250ml water = 7.43 ppm Nitrate x 3 = 22.29 ppm weekly
25 grams kno3 should also add 4.69 ppm Potassium K
15 grams K in 250ml water = 3.27 ppm Potassium K Combined 7.96ppm x 3 = 23.88ppm weekly

If I add 1 tsp of mag sulf on water change day that should be 3.06 ppm Magnesium.

Does that look right? It sounds like it should be to me but the only thing that's throwing me is I've always been under the impression while dosing E.I kno3 values there's no real need for extra K. If I was to add po4 to the bottle only 5 gram would be needed making a 20 ml dose 1.69 ppm Phosphate which seems high to achieve the range of 1-3ppm weekly. Seems like 15 grams of pottasium sulphate is a bit much considering the K from potassium sulphate if I added the potassium phosphate to the bottle would only increase K by 0.7 ppm Potassium.

4.69 + 0.7 = 5.39 x 3 = 16.17 ppm weekly. Still right I guess or within the 10-30ppm.

Anyway just thought I'd check :) Should also add *edit based on a 165 litre tank
 
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