NO3 dosage for Ca(NO3) [EI]

[ltsai]

Hi,

KNO3 is not available in my area without a police permit, thus I bought CaNO3 from aquariumfertilizer.com.

I'm restarting my 60x30x30cm tank from scratch and just flooded the tank for a week. DSM didn't work quite well because my plants were browning out after 2-3 weeks even with consistent misting. Perhaps DSM is not suitable for my hot and humid location.

My regulator is not here yet, thus I'm dosing 2ml of Excel every day with a single 2L DIY CO2. I have a ceramic diffuser that sits under a 300l/h internal filter. My main 600l/h hob filter is with another tank with the rest of the fish.

The lights are on 10 hrs a day with a single 2feet 24W T5HO.

I have the following plants:
1. Java fern
2. xmas moss
3. Cyperus helferi
4. Hairgrass
5. HC
6. Staurogyne repens
7. Fissidens fontanus
8. Anubias barteri var. nana
9. I have yet planted my Alternanthera reineckii 'Mini', since it is still in my fridge.
10. Echinodorus tenellus

I used Wet calculator for the mix. Can someone help me check whether it is correct especially on the CaNO3 portion? I typically dose twice a week, thus I will split the dosage into 2.







Thanks!

 

[ceg4048]

Hello,
It's too much trouble trying to figure out the data on those images. The bottom line is as follows:
Whatever weight of powder you would be dosing KNO3 at, you'll need to use 3X as much Calcium Nitrate by weight to get the same amount of NO3 in solution. The Calcium Nitrate is typically sold as a tetrahydrate which reduces it's NO3 content from 75% to about 25%.

Cheers,

 

[ltsai]

Thanks Ceg.

Because when I look at the forums and various fertilizer calculators such as fertilator on APC or molar mass, the % of NO3 is not about 3 times less.

For example: In 100L of water,
5g of KNO3 will result in about 30ppm
5g of Ca(NO3)2·4H2O will result in about 26ppm

NO3 is about 62% in KNO3 or 53% in Ca(NO3)2·4H2O.

Can you help clarify about the 3X as much Calcium Nitrate when compared to KNO3? Shouldn't it be less?

 

[ceg4048]

Hi mate,
Yes, sorry, my mistake, I miscalculated. You can use the same dosages as you would with KNO3 if we assume 100% disassociation in water. The solubility of Potassium Nitrate is three times higher at 20 degrees C than is Calcium Nitrate, but we would not be anywhere near the solubility limit for our purposes.

Here are the numbers for reference:
Element Symbol Atomic Mass # of Atoms
Calcium ____Ca____40.078 _______1
Nitrogen____N____14.0067 _______2
Oxygen ____O ____15.9994_______6

Molar mass of Ca(NO3)2 = 164.0878 g/mol
Molar mass of NO3 = 2X (14.0067) + 6X (15.9994) = 124.0098 g/mol

For the hydrated form:
Hydrogen____H____1.00794_______ 8
Oxygen_____O ____15.9994_______4

Molar mass of 4H20
8X (1.00794) + 4X (15.9994) = 72.06112 g/mol

Molar mass of Ca(NO3)2·4H2O = 164.0878 + 72.06112 = 236.14892 g/mol
Percent NO3 = 124.0098 / 236.14892 g/mol = 52.5%

Cheers,

 

[ltsai]

Thanks! It's pretty clear now.

Should I be concern about the additional Ca, with respective to the amount of Ca in my tap water?

According to our local forum, EI Dosing for Singapore Water - K, Ca, Mg, Fe, NO3 and PO4 , our tap water has about

PUB


Assuming water change happen once every week (30-50%), you are already dosing:-

Calcium - Singapore water has 50-120ppm (target 10-30ppm)
Potassium - need this as a key nutrients (target 20-3ppm)
Nitrate - Singapore water has 0.5 -15 ppm (target 15 - 20ppm).
Phosphate - Singapore water has < 0.1pp (target 0.5 - 2 ppm) So need to dose a little at water change
Magnesium - no mention in Spec, so may need to dose this
Fe - Very low in Singapore water - definitely a must dose.

Water from tap is

PH - 7
KH - 2 (need to buffer up to 3-4dh)
GH - 5 (measure of Ca and Mg)

 

[ceg4048]

Hi,
Well high Calcium water can be annoying because it tends to leave stains. Also, it raises the conductivity of the water which has a negative effect on soft water fish, but most plants do not really care. There may be a few that struggle, such as Rotala Macandra or Tonina but I doubt very much that you will see any negative consequences as a result of high Ca.

Cheers,