Who's good with math ? *lol*

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Xzap

Aquarium Advice FINatic
Joined
Jun 29, 2005
Messages
587
Location
Triad, North Carolina
I need to start dosing my 90 gal again and need some help with my calculations. My growth is great and so is the BBA.

Based on the EI, I'm coming up with this:

20 gal high standard tank
A Typical Dosing Routine
1/4 teaspoon of KNO3 3-4x a week (every other day)
1/16th-1/32nd teaspoon of KH2PO4 3-4x a week (every other day)
Traces added on off days as the macro nutrients, so 3x a week, 5mls each time.
SeaChem Equilibrium 1/8 teaspoon after water change.
My 90 gal:
4.52 tsp KNO3 a week
1.08 tsp KH2PO4 a week.


Does this look right ?

thx,

dave
 
Not to me, my 90 uses about 1-1 1/2tsp KNO3, 2-3tsp Potassium sulfate and about 1/2tsp of KH2PO4 over a week. Do your nitrate and phosphate tests fall in line for proper levels?
 
Those numbers may or may not be right. Even with EI dosing you need to have a general idea of how your tank uses nutrients.

For example, my tank is hardly ever low on nitrates. If I dosed 3.5tsp of KNO3 per week, I'd have a greenwater nightmare.
On the other hand, I have to add phosphate about every day. And since I dose little KNO3, I dose a lot more K2SO4.

And 1.08tsp of phosphate in 90gallons is 10.61ppm. That seems excessive, even spread out over an entire week.

I think you need to bookmark Chuck's calculator page, or download the Windows version.
http://www.csd.net/~cgadd/aqua/art_plant_dosage_calc.htm
 
It should be approx 1/8-1/4 tsp of KH2PO4 3-4 times a week, so 3/8tsp-1tsp total a week. Since exact numbers are not important under pure EI, you can mess with it. I would go on the low end for KH2PO4 dosing with high bioload and feeding, fwiw. As you know, spreading the dosing out through the week is important -- I'm guessing you're putting the weekly dose into your Evaporation Compensation System?

Like Simpte, I understand and find EI to be a method that eliminates the variable of macros under high light, and isolates CO2. If you have algae and follow EI, increase CO2 first. HTH
 
Thanks everyone for the help.

I'm pumping the c02 into it.

CZ.. I don't have an ECS on the 90 so I'll be dosing by hand over the 7 day period.

Thx,

Dave
 
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