# the Fertilator



## wearsbunnyslippers (Dec 6, 2007)

the Fertilator - this is the nicest ferts calculator i have seen...

it works out relative concentrations based on tank size, and also how the different compounds compound the dosage, so if you add kno3 ( saltpeter ) for nitrates and kcl ( no salt ) for potassium, it works out the actual concentration of k from them both, really nice!

for my 50g tank with commonly found compounds, it recommends:

1 teaspoon kno3 ( saltpeter ) for nitrates and potassium
2 drops nah2po4 ( fleet enema / lenolax ) for phosphates ( worked out with 20 drops = 1ml )
0.3 teaspoons of mgco3 ( climbing chalk ) for magnesium
3 teaspoons of caco3 ( plaster of paris ) for calcium

this will give me a relative concentration of:

no3 ( nitrates ) = 16.85 ppm recommended 10-20
p04 ( phosphates ) = 1.8 ppm recommend 0.5-2
k ( potassium ) = 10.62 ppm recommended 10-20
ca ( calcium ) = 13.57 ppm recommended 10-30
mg ( magnesium ) = 3.05 ppm recommended 2-5

that sounds so much easier than all the other complicated pmdd recipes i have seen.

i am just worried about adding climbing chalk and plaster of paris to my tank, i do not want a milky mess, any tried this before?


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## jjp2 (May 24, 2008)

A lot of us use what is called Estimative Index or EI and use the Fertilator for determining how much to dose. This method calls for a weekly water change to reset the levels so that the accumulation of solids (the milky mess) is reduced/eliminated. The method recommends 50% Water change weekly, some people do less.

Your numbers above don't account for any nutrients already in your water or that you should dose every other day. 

I have a 60 gallon tank and I dose 3/4 TSP KNO3, 3/4 TSP K2SO4, 1/32 TSP KH2PO4 every other day. On the other day I dose CSM+B (10ml of a 2 TBSP in 250 ml water mixture).

I suggest that before you add anything to your tank you do a little more reading on EI so you understand how the nutrients are used (each tank varies in the uptake by the plants), the accumulation in the water, the reset and know you can adjust based on your plants and tank conditions. This will prevent you from having a milky mess.


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## plakat (Mar 2, 2008)

Do you need to add calcium and magnesium to your water? I think pure CaSO4 should be fine but I thought that MgCO3 didn't dissolve well in water. Maybe I am wrong though.


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## wearsbunnyslippers (Dec 6, 2007)

@jjp2 - i have read about EI, thanks man, i am not worried about the no3 or po4 build up, i understand the excess is removed by the water changes, i just wanted advice on plaster of paris and climbing chalk, i do not want a milky tank!

@plakat - sorry man, it should have been caco3 not caso4. i do sport climbing in my spare time and mgco3 seems to dissolve pretty well, never tried it in my fishtank though... not sure if i need to add it, just dont want it to be a limiting factor.


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## Gatekeeper (Feb 20, 2007)

Only thing that bugs me on that calculator is the PO4 box always disappears after you hit "calculate"


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## plakat (Mar 2, 2008)

wearsbunnyslippers said:


> @jjp2 - i have read about EI, thanks man, i am not worried about the no3 or po4 build up, i understand the excess is removed by the water changes, i just wanted advice on plaster of paris and climbing chalk, i do not want a milky tank!
> 
> @plakat - sorry man, it should have been caco3 not caso4. i do sport climbing in my spare time and mgco3 seems to dissolve pretty well, never tried it in my fishtank though... not sure if i need to add it, just dont want it to be a limiting factor.


My bad I typed the wrong thing but i think CaCO3 should still be fine if pure. Is your climbing chalk pure? From my understanding a lot of the brands add chemicals to help absorb sweat.

Test your water first. If you don't need to add any then don't. That solves all your problems right there. Also make sure you need to add the amount of nitrates and what not because they can reach toxic levels if you keep dumping them in at a rate faster than the plants can use them, even with a weekly water change.


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## White Worm (Aug 22, 2007)

gmccreedy said:


> Only thing that bugs me on that calculator is the PO4 box always disappears after you hit "calculate"


I noticed that also. I closed it and went back in and it stayed the next time.


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