what can I use to boost NO3?

kevensquint · Jan 17, 2015

Hello, after doing some searches, it seems KNO3 is the chemical commonly used to boost NO3. It is not legal in my area. I could get calcium nitrate or magnesium nitrate. Would those be OK in my reef?
My nitrates are extremely low, even with lots of feeding and fish. I would just like to have 1 or 2ppm instead of zero. Thanks

Randy Holmes-Farley · Jan 17, 2015

You mean a DIY? There are companies like Brightwell that sell it.

For KNO3, look for stump removers.

If not, the others are fine, but likely harder to find.

kevensquint · Jan 17, 2015

I mean adding a chemical manually to my tank to bring NO3 up from 0ppm to maintain 1-2ppm. I figured if potassium nitrate is fine, calcium nitrate would be too. No? It is sold in a local hydroponic shop as fertilizer.

Birddog · Jan 17, 2015

kevensquint said:
I mean adding a chemical manually to my tank to bring NO3 up from 0ppm to maintain 1-2ppm. I figured if potassium nitrate is fine, calcium nitrate would be too. No? It is sold in a local hydroponic shop as fertilizer.

Basically KNO3 (potassium nitrate) is a fertilizer as well, just like calcium nitrate. I use them both quite a bit as grower of turfgrass. Careful with a purchase of calcium nitrate though from a distributer that's selling it as a fertilizer. It is a very hydrophilic substance and often treated (coated) with other compounds so that it does not take on atmospheric moisture. Those other compounds, if I were to guess, are not likely to be reef safe. Potassium nitrate is also known as saltpeter and one of two main components of gun powder... probably why it's regulated where you live.

kevensquint · Jan 17, 2015

That's good to know, I guess I won't risk CaNO3.

Randy Holmes-Farley · Jan 17, 2015

FWIW, as a pure chemical, the calcium salts are fine.

UK_Pete · Jan 17, 2015

I needed some nitrate recently and added some 5M nitric acid I had to an excess of calcium hydroxide (kalk), which I believe makes calcium nitrate. Dilute nitric acid is easily available pretty pure on ebay and kalk is for tanks anyway. I had the calcium nitrate fertilizer too but thought it might contain things like phosphates since its for agriculture. I find having the mineral acids nitric, hydrochloric and sulphuric in the shed is quite useful as they have multiple uses. This way, you know exactly how much nitrate is in the final solution too (whereas with solids they often are hydroscopic requiring baking, probably not wise with nitrates).

I'm not 100% sure of the calculation so don't take this as gospel, maybe Randy can confirm, but I reasoned that since 5M nitric acid has 5 moles of acid per litre, thats 5*62 = 310 grams nitrate per litre (62 grams is the weight of a mole of nitrate). So I made a solution with 10ml 5M nitric acid added to enough kalk that it did not all dissolve (so there was a residue of kalk in the beaker), and then added enough water to make the total volume 100ml. This solution then has 3.1 grams total nitrate in it, or 31mg per ml (31000 ppm). Adding 1 ml of this to a 100 litre tank would increase nitrate by 0.31 ppm, or adding 1 ml to a 100 US gallon tank would increase nitrate by 0.081 ppm. I'm using it every now and then to keep my nitrate around 2 ppm.