Sharing for users of Calcium Nitrate for EI

[edwardchuajh]

Hi All,

Just wanted to share my initial foray into EI dosing with DIY dry fertilisers. (Moving on from Seachem line)

Due to many reasons, we're now unable to get KNO3 (Potassium Nitrate) in dry powder form locally. The alternative to use here would be Ca(NO3)2 (Calcium Nitrate).

There are a lot of past literature on using the usual Potassium Nitrate and Potassium Phosphate for all your dosing needs, but not so much on Calcium Nitrate.

Here are a few points I hope will help future aquascapers trying to use Calcium Nitrate for EI dosing.

1. Calcium Nitrate is highly hygroscopic, where it will absorb atmospheric water and turn into a sticky, viscous liquid. Just be careful when scooping teaspoonfuls of it.

2. Calcium Nitrate WILL react with Potassium Phosphate. Totally forgot about this and mixed 1Liter worth of fertilizers, only to see Calcium Phosphate being precipitated out of the solution.

So take note of this if you are intending to pre-mix solutions instead of dry dosing!

---------------------

For anyone interested in my set up. Please let me know if you see anything horridly wrong!

Tank: 20gal (2ft tank)
Water Volume: ~65 liters
Light: 2 x 24W T5HO (7000K)
CO2: Pressurized, maintaining at 25-30ppm

I bought Calcium Nitrate (1kg), Potassium Phosphate (500g), Potassium Sulfate (500g), and LUSHGro Micros (120ml) from EcoCity.

I simply bought 2 bottles of 500ml Distilled Water. Helpful to pour a bit of the water out, add the fertilizers, then top the bottle back up.

In Bottle One, I dissolved 4.5 teaspoons of Calcium Nitrate into the bottle.

In Bottle Two, I dissolved 1.5 teaspoons of Potassium Phosphate and 1.5 teaspoons of Potassium Sulfate into the bottle.

The dosage each time will be 20ml from each bottle when I am dosing for Macros. This will last you 25 doses, and at 3 times a week, it should last about 2 months before needing to mix another batch.


Sunday - 50% water change, 1 teaspoon EIHO Plant GH plus, 20ml Bottle One, 20ml Bottle Two
Monday - 2ml of LUSHGro Micros
Tuesday - 20ml Bottle One, 20ml Bottle Two.
Wednesday - 2ml of LUSHGro Micros
Thursday - 20ml Bottle One, 20ml Bottle Two.
Friday - 2ml of LUSHGro Micros
Saturday - Rest

[edwardchuajh]

hmm seems like I can't edit the post above. Please note that the 2ml of LUSHGro Micros should be 2 drops instead.

[atolylica]

Hi, thanks for sharing.

I've mixed the 3 macros (CaNo3, K2So4 and KH2PO4) in one pre-mixed solution, and I do see precipitate after mixing. Can it still be used? I've been dosing and it still seems fine for my plants for the past week.

If it's not ok, my question is wouldn't it react in the tank to form Calcium Phosphate in the tank when you dose bottle A and B at the same time?

[leonard6july]

hmm seems like I can't edit the post above. Please note that the 2ml of LUSHGro Micros should be 2 drops instead.

Edwin,

Thanks for clarifying the units.

[edwardchuajh]

Hi, thanks for sharing.

I've mixed the 3 macros (CaNo3, K2So4 and KH2PO4) in one pre-mixed solution, and I do see precipitate after mixing. Can it still be used? I've been dosing and it still seems fine for my plants for the past week.

If it's not ok, my question is wouldn't it react in the tank to form Calcium Phosphate in the tank when you dose bottle A and B at the same time?

Hi atolylica,

I am not too sure about whether it can still be used, but personally I felt better just to make a fresh batch.

From what I've read, the precipitation happens in solutions of higher concentration (ie. premixed bottle). However that is minimal when diluted into the aquarium water.

[thebaldingaquarist]

thanks for the information edward.

I am not a chemist and i nearly flunked my chemistry last time, so this information really helps!

[Shadow]

2. Calcium Nitrate WILL react with Potassium Phosphate. Totally forgot about this and mixed 1Liter worth of fertilizers, only to see Calcium Phosphate being precipitated out of the solution.

If not mistaken, with my limited understanding on high school chemistry (20+ years ago), you are actually making KNO3 and Ca(H2PO4)2

2KH2PO4 + Ca(NO3)2 -> 2KNO3 + Ca(H2PO4)2

Those who are in chemistry feel free to correct me

[edwardchuajh]

Yep.. I was thinking the calcium phosphate precipitated out will lock up the phosphates, thereby wasting your dosing.

Similar to how it's advised not to mix Iron with Potassium Phosphate as it will form iron phosphate and precipitate out of solution.

You still get the nitrates, but phosphates is greatly reduced in the dose.

Sent from my SM-N9005 using Tapatalk

[Shadow]

I give you a hint, mix Ca(NO3)2 with the other fert

[edwardchuajh]

Hehe I decided to separate them too. They should just let us buy KNO3 mixed with other ferts to prevent all these issues.

Sent from my SM-N9005 using Tapatalk

[milk_vanilla]

Or dose them into different timing? Day and night, for example.


Sent from my iPhone using Tapatalk

[Phillipians]

I did not have CANO3, as Hydroponics provided N in the form or Urea.
Actually I tried to do some basic maths and mixed the powders into solutions such that each squirt from the bottle (approx 2 - 3ml) will give me the dosage for 1 week.
N from Urea, K2SO4 for K, and Kh2PO4 for P and a little K.
3 different bottles for each . It wouldnt be wise to premix all as I think we normally add as we see the condition of the plants.

[Phillipians]

Just in case you are interested in how I dose:

20g per 500ml for Urea, KH2PO4, K2SO4
Mine is a 2 x 1.5 x 1.5ft tank with fast growing plants like: Elatine Tiandra, Downoi, Hygrophilia Species (Stem plant not sure the ID: Purplish underside leaves), Narrow leaf java fern, Xmas moss, alternanthera reineckii sp mini.

After a weekly water change:
Day1: 15 ml Lushgrow Macro + 1 Squirt Urea + 1 cap Seachem Excel
Day 2: 2 drop Micros
Day 3: 1 squirt K2SO4 and Kh2PO4

Then I add another 1 drop Micros in day 5.

Seems to be doing well. 3 BPS per sec CO2 reactor SERA.

No algae the past 3weeks - 1 mth. First time no algae. But water change must be diligent.